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Unique Visitors = 1/10th of Unique IPs? 261

Max Fomitchev submitted a little blog entry where he proposes that the ratio of unique IPs to actual unique users is 10:1. This flies in the face of the numbers you usually see attached to these sorts of things. I'm not sure about the logic he uses to come up with these numbers either.
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Unique Visitors = 1/10th of Unique IPs?

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  • 10 was arbitrary (Score:5, Insightful)

    by op12 ( 830015 ) on Tuesday May 02, 2006 @02:16PM (#15247364) Homepage
    The 10 was a hypothetical...the only point was that you can't trust the number of recurring visitors that a site reports because they users come back with a different IP (obvious) and get counted twice. Couldn't one use cookies and IPs in combination to get a better gauge? The IP may change but the cookie would not. Sure some may delete it, but it'll still improve accuracy at least a little bit.
    • Exactly. How many people log into their webmail or their MySpace or whatever from their home computers, their laptops, their work computers, the library, their school's connection, etcetera? Almost everybody.
      • Re:10 was arbitrary (Score:3, Informative)

        by ADRA ( 37398 )
        How many user are sitting behind my company's single routable IP address? Hit: Its over 1000.

        This sways the number in the opposite direction. The number the story's based on is completely baked. You could attempt to statisticly estimate the number of unique users/ip on your site with some effort, but you can't get a real concensus between one sight and the next. The reason is demographics. If you take a mobile enabled sight, you're almost always guaranteed to get at least 2 IP's per user(one mobile usabili
    • by MikeFM ( 12491 )
      My experience is that a lot of users use cookie killing software that removes cookies every time the browser is closed or just reject cookies altogether. Also many users seem to use multiple browsers and computers even within small time periods. Counting unique visitors is really quite difficult. Still, if all site's play by the same rules on counting the number still has some meaning. Unique IP address within a given timeframe is probably a decent metric still.
      • Re:10 was arbitrary (Score:3, Interesting)

        by op12 ( 830015 )
        My experience is that a lot of users use cookie killing software that removes cookies every time the browser is closed or just reject cookies altogether.

        My bet would be in the grand internetscape, this number of users is actually quite small and that most do not reject or remove cookies (at least not often).

        However, the point was a better gauge, not a perfect one. Requiring login would resolve most issues of users from different locations or even multiple users on the same computer, but few people are
        • Re:10 was arbitrary (Score:2, Informative)

          by MikeFM ( 12491 )
          I've been surprised on the cookie issue. I thought nobody would block cookies but then I've had to resolve a number of issues with users who do block cookies. Evidently a few anti-spyware type programs commonly used block cookies by default. A real pain in the ass to figure out to tell the truth. This whole anti-cookie thing drives me nuts since they really are harmless for the most part.

          Proxy servers add some issues too. I'm pro-proxy as it does reduce load on servers, speed up the user's experience, etc.
    • by Black Perl ( 12686 ) on Tuesday May 02, 2006 @02:26PM (#15247488)
      First of all, a DHCP server is typically going to give you the same IP address each time your computer requests it, unless there are more users than IP addresses, in which case there will be some shuffling. But that tends to be when there are more users than available IPs.

      There are entire domains hidden behind a NAT device of some sort. This would be many users per IP address. TFA didn't mention this at all.

      So I think TFA is indeed arbitrary, and also wrong.
      • Home internet users are usually grouped into big subnets of IPs that are constantly being shuffled around. IP addresses expire and reconnect on a schedule, houses have power failures, modems do something funny, or whatever. IPs in a huge pool are being retired and reassigned constantly. The bigger the pool, the lower the chance of obtaining the same one before someone else's modem nabs it.

        If they offer it, ISPs charge extra for static IPs. Nobody would pay extra if it wasn't an issue.
        • Actually the oposite should be true. The bigger the pool the better your chances are for getting the same IP. When you release your DHCP lease from the server or it expires before your client renews it the server still has that address assigned to your MAC address. The only difference is the lease is inactive. If there are addresses in a pool that have never been assigned and a new client connects it will use those addresses first. If there are none then it will start checking the inactive leases. It
        • Any kind of broadband[1] is always-on, and so needs an IP all of the time. The easiest (and therefore most common) way of implementing this is to give a user the same IP all of the time. Since users will be refreshing their DHCP leases at different times, it is difficult to shuffle them between users (and will break things if they have active connections at the time). If your modem/router/whatever is turned off for a period, however, then it is quite likely that your IP will have been allocated to someon
          • If I used broadband the way my ISP (AT&T) envisioned it, it would connect to my single PC. Whenever my PC was on, I would be connected. Whenever it was off, I would disconnect.

            But I don't use it like that. I have a NAT router attached to the DSL modem. The router maintains my connection 24/7. The keep-alive is set as long as is allowed - 6.999999 days or something like that. And, when it renews, I'm down for less than a second.

            Thus I've maintained the same IP for as long as I have checked. Of cou
      • by the melon ( 89066 ) on Tuesday May 02, 2006 @02:46PM (#15247688)
        Yeah, here at Sun there are nearly 40 thousand people that connect through 40-50 different proxy servers. That is a thousand to 1 in the opposite direction the article claims.

        And yes, he seems to have no idea how DHCP really works. Even if your lease is expired you will get the same IP address unless the pool has been exausted and your address re-used. I see that as an extremly unlikely thing to happen because it would mean, as you say, that your pool is smaller than your installed base. If you pool is smaller then you will start having issues because x number of customers will always be without a connection because they can't get an address.

        Had he mentioned Dialup users then I would be more inclined to agree because you are very likely to get a different address every time you connect.
      • One place where it is true that users change addresses constantly is dialup; PPP generally doesn't care who you are, or have any concept of a "lease", so generally speaking you'll never get the same address two connections in a row. The number of dialup users is on the way down, but it's still significant (for reference, see Slashdot). But I agree that the effect should be canceled out (or more than canceled) by the effect of NAT routing at offices, schools, libraries, and other big institutions.
      • True, but some broadband providers intentionally hand the client a different IP when their lease expires in order to:

        a. Prevent subscribers from running servers without paying for a static IP. While dynamic DNS services can be a workaround much of the time, it doesn't work very well with SMTP or other cases where DNS caching can cause issues.

        (or, if you ask the provider)

        b. To decrease the likihood of crackers breaking in your computer.
      • --

                * MOD THIS UP INSIGHTFUL!!!! by Anonymous Coward Wednesday February 30, @09:34AM

        So now we have phishing signatures? It seems like this signature make it looks lika other user have requested a mod up on him, I would mod it down if I had the points, just for the use of low tatics, even though I do think the comment content is okay.
        • This sig has been in use for a while. I've seen it before, but it's obviously not a real comment; the link text isn't coloured and there bullet is not the right character. When I saw it first (a year ago?), it seemed an obvious joke, and I laughed a little. Perhaps you need to lighten up a bit?
          • Well, in the comment the character was right and the signature was correctly idented. The date and the fact that it is not a link is a clear signal of it's not being a real reply.

            Well I didn't see the point of this kind of joke, and quite clearly it could fool someone, and having a good feedback in a fake response could aid him to get some extra karma. I don't think this is fair play or funny, but I don't care much to karma either, but many people here do care, and I was stunned to see this kind of "phishin
        • Yes, well, if I had mod points I'd give you +1 Overreacting. I guess we can't all get what we want.
      • Hmm, well TFA was speaking to DSL users, who generally connect via PPPoE. PPPoE, while it does dish out IPs a la DHCP, does not have a lease file that associates user mac addresses with the IP they were handed on previous connections; users generally will get a different one every time they connect just like dial-up (aka PPP). I would say router-based PPPoE connections drop and reconnect at least once per week on average.
      • It doesn't quite work this way for PPPoE (which is why he singled out DSL). PPPoE is more like really-high-speed dialup.

        I'm not sure about TFA's logic overall, but he had a point when it comes to most contemporary DSL.
      • by sd.fhasldff ( 833645 ) on Tuesday May 02, 2006 @03:38PM (#15248206)
        My IP has been for a really long time now. Ever since I got my first internet connection, actually. That must be why it's such a "nice" number and not those horribly complicated ones other people always seem to have.
    • uses a cookie to determine if someone has visited before, and so people who don't retain cookies throws off my blog's stats. I see visiotrs counted as two, when clearly they must be the same person. Dialup with DHCP addresses also hampers accurate counts about who is returning, if they've deleted the cookie. And computer labs or vast networks like Community Net in SK use proxy servers, as does AOL I think.
    • by bbsguru ( 586178 )
      Oh Puh-lease! EVERYONE knows the REAL number is 11.32019 per IP address. This is just silliness! There is no magic number that works everywhere; fuggidaboudit. If it matters that much to KNOW the real number of unique visitors, ask each one for a scan of their right thumbprint, and then create a database. I thought so.
    • Crazy article (Score:3, Informative)

      by TheLastUser ( 550621 )
      You can't trust web stats, that much I agree with. The rest is a bunch of hand waving.

      DSL customers do not get a new IP every time they turn on their computer. Maybe some do, but my IP changes maybe once every few months, max.

      He fails to mention the effect of NAT'ing and mega proxies, both of which are in heavy use and have the OPPOSITE effect. All of AOL emerges through a small number of IP addresses, clearly more eyeballs than IPs.

      I agree that IP != eyeball, but that's it, there could be more eyeballs tha
  • so... (Score:5, Funny)

    by gEvil (beta) ( 945888 ) on Tuesday May 02, 2006 @02:17PM (#15247377)
    So, he's saying my website has 1/10th of a visitor?
  • by Anonymous Coward on Tuesday May 02, 2006 @02:17PM (#15247382)
    I help keep this in balance by using my neighbor's wireless, that IP has a load of unique users.
  • Maybe not... (Score:2, Insightful)

    by Anonymous Coward
    I've hosted several servers from home for years at a time without my dynamic IP address ever changing, and I've known many others in the same situation. I think this 10x rule might be a bit extreme...
  • I guess it depends on the definition of "visitor". Maybe the site tracks unique IP addresses, or maybe it ignores them where the client has a permanent cookie installed.

    However, I can attest that my ADSL connection is pretty DHCP heavy. Sometimes my IP won't change for weeks, but I've had 5 or 6 IPs in 24 hours on several occasions.
  • IP addresses do not correspond to users because of dynamic IP and proxies.

    Cookies are a much better indicator of what browser you are communicating with.

    Also, most spiders don't bother with cookies, so that's another way to tell something isn't a real user.

    Unfortunately, some users disable cookies. And then all you can do is fall back on their IP address.

    It would be nice to see cookie-tracking support in Open Source stats engines like awstats.


    • []

      Look for %u in defining a custom log format for analog, which can be used with the user report capability to give you session ID information (easily paired with Apache's mod_usertrack .html []). 504311 [] is a good read on the module as well.

      You have to get your log formats set right, but I believe this is what you're looking for (I don't use awstats, but it's most likely possi
    • Yeah, but my IP address is a NAT with 3 computers on it (desktop, big laptop, small laptop). I dual-boot, so that's 6 operating systems. I mostly use Firefox, but I sometimes use IE or Konqueror, so that's 12 different browser installs, none of which share cookies, all of which are just one unique user. And I delete my cookies or reinstall an OS now and again.

      Oh, and I have another Firefox+Konqueror at work, which I sometimes browse through via X-forwarding or nx (or physically being there, obviously)... so
    • Re:Use cookies (Score:3, Insightful)

      by gstoddart ( 321705 )

      Unfortunately, some users disable cookies. And then all you can do is fall back on their IP address.

      Of course we block cookies. Because most of the cookies you get offered are 3rd party to the site you're visiting and just crap so gator and all of that other junk could keep track of you. I only accept cookies coming from the site I'm visiting, and then only if I say YES. It took a very long time to teach a lot of people they needed to be more cautious with cookies, because there were a lot of privacy iss

  • But... (Score:5, Funny)

    by xpird ( 207937 ) on Tuesday May 02, 2006 @02:20PM (#15247422)
    Can he find a formula for the number of /. articles posted vs. the actual unique articles?
  • I think the moral of the story here is that you can glean no true information as to how many visitors your site really has by unique IPs. This convenient unique visitors = 1/10th of unique IPs idea is no more accurate than simply assuming each new IP is a new visitor. There will be people who visit your site from 10 different locations and thus 10 different IPs, and there will be whole families on one IP visiting your site. Or perhaps one of those 10 different locations one person uses is used by others. Si
  • I see what the guy is saying - dynamically assigned IPs at clients mean that one person can view a site from multiple source IPs over a period of time. Both DSL and cable use dynamic IPs - but they are not often disconnected/reconnected, and when they are, DHCP is likely to pull the same IP address back anyway.

    Besides that, think of all the people at work on internal LANs, each presenting the same public IP source address to the same web server. This effect more than makes up for the dynamic IP nonsense t
  • WTF? (Score:4, Insightful)

    by giorgiofr ( 887762 ) on Tuesday May 02, 2006 @02:21PM (#15247432)
    This argument is flawed. Logging to Slashdot now from my house and two hours from now from my friend's house should count for two visits, and so it rightfully does. The article writer seemed to have a problem with this? ZOMG 2 different IPs...
    And if my IP has changed but I'm still here... that's because I haven't surfed for many hours at least otherwise the lease will be renewed and the address will stay the same. So it should still count for two visits. Duh.
    • So you are saying that by going to your friend's house, you are now a different person (aka, a different unique visitor)? It may count as two separate visits (which is not what is being argued here), but you are still the same unique visitor. Counting IPs alone does not provide an accurate representation of how many unique visitors view a site. Your example only helps to demonstrate this.
      • The unique visitor statistic you're talking about is completely useless anyway. Another way to phrase it is: "how many pairs of eyes have seen this site, in total, ever". So if I see the site, I'm forever counted as having seen it once, and no more.

        From the point of view of ad impressions, this would imply that ads have exactly one chance of having an effect on a visitor, no matter if there's several hours, days, or weeks in between views. But that's not how ads work, you want to show it to the same pair o

    • Two things:

      1) He is interested in counting the number of unique visitors to a site. Not unique computers. If you visit a site from a home computer, a work computer, and a computer at some internet cafe somewhere, it will show up as three different IPs, and be counted as three different unique visitors. However, you are only one person, so, if we are concerned with counting unique visitors, it has just overcounted you by 2.

      2) Also, even if you are using just one computer, there is a high likelihoo
      • Assuming you are on DSL (cable, as well, but he ignores this fact), you are probably getting an IP address via DHCP, which means that the server issueing that address could issue a new one every time you connect. Over the course of a month, you may get several addresses, each one counting as a unique visitor. Again, you are being overcounted.

        My cable modem only gets disconnected if the power goes out, and if that does happen, it reconnects long before my DHCP lease expires. I've had the same IP for over a
    • You somehow have been modded up. It seems that at least you and a moderator need to learn the definition of unique.
  • by hurfy ( 735314 )
    Fixed 4:1 ratio here tho i can't speak for anyone else.
    1 office and 3 home computers.

    10 seems a little excessive, timeframe probably matters to actual ratio: unique per day? month? year?
  • I do most of my news browsing at work, where several hundred people show up as one IP (home computer is exclusively for WoW).

    Besides, the assumption that stated unique visitors = actual unique ip's is innacurate. Lots of companies track users with some kind of UID cookie, for more accurate stats. True, this isn't perfect either, and will reset when users wipe their cookies or it expires, but is probably closer to the real number than ip's.
  • Ooh, wow... IP's aren't good indicators of uniqueness... I'm sure the Slashdot editors will tell you how valid that is when they're troll hunting.

    But I don't think dynamic DSL IPs are that big of a problem. What about DSL users that are connected 24/7? My DSL provider rarely kicks me off and I can hold the same IP address for weeks.

    What about laptop users at wireless cafes or users who post/read from work? Surely the same IP that reads a tiny website from home is likely also the "same IP" that reads it f
  • A) He's talking about IPs reported in site visitation stats, not available IPs "out there."

    2) He skips a few major technical details about the IP system itself.

    d) He's mulling over a random loopy theory in a personal blog post, which isn't quite news. If it were, I'd be William Randolph Hearst by now.

  • If you are only using IP to generate your visitation metrics, then you're fooling yourself, for the reasons outlined in the blog. You can't guarantee an IP is unique to a user, any more than you can guarantee that a user is unique to an IP (think Internet cafe or library; different users, same machine with potentially the same IP)

    You have to use a combination of log data to try and scope out exactly who's visiting: IP, browser type (can't count robots in your stats), membership id (if the site uses/requir

  • ... but didn't read the detail. A DHCP client gets the same IP address it had previously, so unless the pool is in short supply of free addresses it will get the same address as before.

    And why does he suggest that DSL clients have static addresses while cable users have dynamic ones?

    Also, most home users (I'm allowed a presumption too) have routers instead of bridge/modems or PCI card modems, and they are kept on all the time. While the router is powered on it will keep renewing the existing IP address.

    I ha
  • IP says very little. Dial-in users (yes they still exist) get a new one every time they dial-in.

    I am a little puzzled by his assumption that DSL users get a new ip while cable users have a static one. I had a DSL account with a static ip and a cable with a changable one.

    Also if you got a good ISP that doesn't drop your always on connection you won't be changing your IP all that often. Hell even my crap cable provider rarely changed my ip.

    So no, for a "large" site you can't really determine unique visitor

    • Also if you got a good ISP that doesn't drop your always on connection you won't be changing your IP all that often. Hell even my crap cable provider rarely changed my ip.

      Even if it does drop connection, if you renew your lease within the TTL, you'll get the same IP anyway, unless the server is configured otherwise.

      On Comcast, my IP only changed if I brought up machines out of order. So long as my server was the only thing hooked up to the cable modem (to do firewalling and NAT) then the IP never c

  • wait a sec (Score:5, Interesting)

    by hurfy ( 735314 ) on Tuesday May 02, 2006 @02:25PM (#15247479)
    I forgot something.
    What about the other way?

    Do they see the 10 people on the office NAT as one IP ?!?

    That would skew it in the other direction and average things out wouldn't it? Now 10 is definately excessive.
  • Nobody knows exactly how many true unique visitors there are to a given website. And given the various ways to determine what is "unique", this muddles the pie further.

    However, the important thing is, advertising rates aren't affected since they have been market-corrected for this. If an advertiser can make money, he will buy. If he can't, he won't. Whatever the true number is, it's already been factored in.
  • by QuietLagoon ( 813062 ) on Tuesday May 02, 2006 @02:29PM (#15247517)
    All of the millions of AOL users visit websites via a couple of hundred cache servers. You won't see a lot of different IP addresses for the AOL visitors to your site.

    I wonder if the other major ISPs do the same.

  • If you use [] then it counts number of visits, the same IP is still the same visit if the user of that IP (re)loads a page within 30 minutes. After that it's a new visit... And it should be safe to assume one visit is one user. Saying that 1:10 is the ratio for IP/users is simply saying that every user will visit the site ten times - which seems like a worthless number without limiting it to a time-period and also, the number seems to be taken out of no-where.
  • Single IP addresses could be multiple people. Check.
    Multiple IP addresses could be individual people. Check.
    Cookies cannot be trusted to be persistant, since people routinely clear their caches. Check.


    Not all DSL customers are on dynamic ip.
    Not all cable customers are on static ip.
    The reverse of the above is also not true, so why even get into that?

    So, what can we learn about IP address->Unique visitors from the above collection of information? ABSOLUTELY NOTHING.

    However, you could come up with a
  • We have 54 employees going through one firewall, and having one external IP address. On our company website, only that one IP address shows... So for that IP, it is not 1/10th of a unique visitor, it is 54 unique visitors. His numbers are baseless and skewed.
  • How about the people who connect from behind a router and have the same public IP, wouldn't that have the opposite effect. Sure these people _look_ like the same user, but could easily be a lot more than that.

    If I send my sister a link on our home network, she could go to the site and it looks like the same visitor, etc. Everyone forgets about this too. Surely unique IPs != unique visitors, but it is somewhat close.
  • While there's some validity behind what the article says (althought the 10x is ridiculously high IMHO), he fails to mention the other side of the equation which is multiple visitors from the same IP address. Your home network is almost certainly NAT'ed ... and Corporations are using proxies more and more for outbound connections. I.e. I know of one Fortune-50 company with a couple of hundred thousand employees that has a total of SIX (!) web proxies. You also see this with cache servers, especially stuff li
  • This random blogger (*) proposes something fairly wild without any proof whatsoever. Slashdot reports it simply because it is a wild guess.

    Hmmm... I think I'll guess that there are only 10 unique internet users in the world excluding Comic Book Guy [tm], maybe that will get me reported on Slashdot giving me 10 hits of sweet, sweet advertisement money.

    (*) Well, I've never heard of him.
  • I'd say he'd have to look at a specific population.

    Among college students and younger, it may very well be 10:1, or worse.

    For those of us accessing from work and home. That will be 2:1 assuming the same site.

    For those of us behind corporate firewalls or other traffic aggregate points. It could very well be 1:1000, or higher.

    Without some other data point, unique IP address statistics are next to worthless, except in "We had xxx,xxx average daily last month and xxx,xxx + xx,xxx average daily this month.
  • This talk about tracking people and determining the amount of visitors to a site is somewhat dated. Here is an article from October of 2005 in which, astonishingly, it is revealed that people are deleting their browser cookies so when they go back to a site they are counted as a unique visitor even though they may have visited the site yesterday.

    What the author is pointing out is merely the obvious: when a site says they have X visitors they're making a guess. In fact, this link [] from April 30th both e

  • I almost knew not to read the article on the basis of the statement "the logic he used". The article did not disappoint. The logic he used is irrelevant. The whole argument is pointless because he tried to argue it logically. There are plenty of ways to inflate or deflate this number, however, as above comments have pointed out. One should not try to come at the answer with logic. Just measure it. (Yes, measuring it is not necessarily easy, but difficult-to-obtain right answer is always better than an easil
  • When I worked for a search engine company we relied on a combination of IP address and HTTP cookie to identify unique users. True, many people disable cookies, delete them, etc. but by making use of multiple tracking methods you get a much more accurate idea of usage.
  • by zen611 ( 903428 ) on Tuesday May 02, 2006 @02:49PM (#15247718)
    "Don't trust Stats. Except mine..."
  • bad maths here (Score:3, Informative)

    by Ankh ( 19084 ) * on Tuesday May 02, 2006 @02:52PM (#15247746) Homepage
    There are so many factors here that focusing on one probably isn't sensible.

    Some examples:

    1. Even DSL users can often keep an IP address for several weeks, depending on the ISP.
    2. On the other hand, any sensibly configured home network (OK, that's almost none of them perhaps) has a hardware firewall, or has multiple users with "connection sharing", so multiple users per IP.
    3. Most offices use a firewall with NAT, so all of $BIG_COMPANY appears to be one IP address.
    4. Some ISPs run an HTTP proxy -- AOL is one example -- so that static pages will only be fetched once per Expiry period (or once per day) even if everyone on AOL looks at them.
    5. In any case, numbers of users is not the same thing as number of IP addresses; sites are reporting based on cookies or on login codes.
    6. small numbers like 10 sometimes take on different values. Er, OK, no they don't but I'm bored.

    I don't really know why it matters in any case. For advertising, clickthrough rate is more important than number of users, and they are not very closely related. Sadly, the poorer your site's navigation the higher the clickthrough rate (and the fewer pages on your site people will see each visit, as the ads take them away sooner).

  • I'm not sure about his article and his formula, but it is already a debate in the web analytics industry. [] Even using cookies it's nearly impossible to get correct unique visitor counts and that is why the industry is moving more towards unique visits, because a visit is a visit, it doesn't matter who the visitor was... The only way to really measure how far off visitor data could be is comparing unique customers (cusomter id) to the number of unique visitors they create (the
  • by wbhauck ( 629723 )
    Proxies could, especially ISP proxies (AOL, anyone) can hide potentially 10,000's of unique users.

    Also, as far as i've seen DSL IPs don't change that often.
  • So other than advertising a blog entry that, at best, is deeply flawed due to the complete misunderstnading of NAT, DHCP lease times and the fact that no reputable site uses IP addresses as a basis for their stats, what exactly was this article about?
  • by EvilMagnus ( 32878 ) on Tuesday May 02, 2006 @03:14PM (#15247989)
    It's that this is a Marketing Person who has realised that IP != Unique User.

    That places him amongst a tiny minority of marketing people, even if his reasoning and ideas on methodology are just as batshit insane as the rest of his kin.

    • Actually, if you go back and look at the rest of his blog [], you'll find that he claims to be a developer. In fact, when he attended University of Tulsa, he was apparently surprised to find that some few students there were actually smarter than he was! So he's clearly a very smart developer!

      No, but really, if you browse the rest of his blog, he just comes off sounding like a dumbass. Well, more of a dumbass than he sounds like just from this nonsense about unique visitors to his web site.
  • I've got cable with supposed dynamic addressing but in truth it has remained the same for over a year. There was a time it changed every few days but I presume they upped the allocations or whatever. I think it's interesting what this guy is saying but (as many people are saying) the data is very confounded and many different reasons could apply.

  • I did a quick analysis of a 250,000 line entry server log. I counted unique ip addresses, unique useragent cgi values, and then the number of unique combinations.

    A useragent value looks like this: Mozilla/4.0 (compatible; MSIE 6.0; Windows 98; .NET CLR 1.1.4322)

    Although even this is hardly reliable since useragent can be faked, and useragent isn't unique enough to be a client fingerprint -- its still helpful in this context.

    One can make the assumption that a given user's "useragent" value isn't going to to change much on a day to day basis, though it will not stay the same over time as vesions get updated. GENERALLY speaking, the same IP address but different USERAGENT values would indicate different people from behind the same NAT firewall, or different users assigned the same DHCP address.

    Here's what I got for results -- it looked like counting only unique IP's gave you only about 85% of the unique hits.

    Total Hits Looked At: 249861
    Unique IPs: 10309
    Unique UAs: 1578
    Unique Combos: 12232
  • While he has a point (I visit particular sites from at least two different networks on a regular basis) there are a couple things he doesn't take into account.

    Firstly, every DSL I have ever worked with is a peristent connection. (Why would anyone bother with an on-demand DSL?) It may not be a fixed IP, but it is a pretty darn sticky IP. It only changes when one endpoint of the DSL circuit is reset, and that generally doesn't happen much more often than monthly. If you're tracking unique IPs over the life of
  • I urge you people! Mandatory registration on each site! Three names, e-mail, address, age, sex, and social security id!

Logic is the chastity belt of the mind!