If your spammers are using Turk or any other form of human labour, all bets are off. I can't think of any reliable way to stop the captcha being captured and played back to another person. A time limit would make it harder, but isn't a problem if you can get your solvers working real-time.

Letter substitution or jumbling would totally muck up a screen reader, though. Humans' very efficient reading only works with visual reading, in which case you're back to square one, a visual captcha.

If you use something like wikipedia for your legit sentences then cracking it is simple. Google each sentence, the one which turns up exact phrase results is legit.

We don't need to argue about whether they exist or not, or say they might or probably do exist. Get the people who claim to have magic ears, apply double blind testing, and now we know.

I bought Tchaikovsky's Violin Concerto on Amazon. Great quality MP3s and all, but apparently they were ripped from an ancient piece of vinyl with a frankly ridiculous level of crackle and several loud pops which made me fear for my speakers. (I wouldn't have minded except the 30s preview carefully avoided any obvious noise). Happily I got a refund.

Genuinely not sure whether joking or audiophile.

Hang on, what? Are you saying if I write something, then repeat what I wrote in an anonymous context, that's plagiarism?

I wonder if you could get all your programming work done this way, splitting it into small chunks and asking applicants to do them, and turning them all down...

That's not really the point. The point is that you can either make stuff up or be very misleading and lots of people will loudly go along with it (I believe a bunch of people went out and got a lot of signatures on a petition to ban DHMO). I'm sure if you made up something entirely nonexistent or found some other very obscure but pretty safe chemical you could get the same effect, but the fact that it's water makes it all the more amusing (And makes the fact that it's not actually evil more readily apparent to the informed reader).
"Oh well, I lost my moderations but I felt like saying this anyway. And don't blame me if some 'c's are missing, my key is a bit broken." -Cill

But some actual economics will tell you this is only true in a perfect competition, which the mobile market is not. Some providers /do/ do vheaper texts and do not have 100% of the market, proving this. Aalso, there is no reason texts should cost how much sending them costs + sensible markup. Disregarding profits, cell companies have X running costs and so have to get ~X money from somewhere, but not necessarily proportionately to costs. See: rich bohemoths making mad losses on something to get into the market.

If the penalty was the same as the reward, there would be no.disincentive - if you get caught, you just give the money back, if not, you keep it. Since theres a chance you won't get caught, that makes it statistically a net gain to do it.

In this place of the UK, the area code tells you very much where/what you're calling, be it a normal landline, mobile, premium or free number. Even the cost of the number is often specified just in the area code. And if that's not enough there's a website which does premium rate phone number lookups. (Hint: 08 and 09, apart from 0800, are generally costy)

That's fission, they really are pretty different. On a hobby level, fission consists of lots of playing with radioactive things and all that. Fusion consists of putting some gas in a box, turning it on, putting a whole lot of power in and ending up with a different gas in the box.

Indeed, at our engineering department a student society just had one sitting on a table in a corner and didn't mention it, as though it was a completely normal thing to have around.

I think most of the power of the current game comes from the determinism, allowing design of complicated stuff. In order for any kind of pattern to withstand mutations I expect you'd need an awful lot more stuff overall (redundancy?), i.e. bigger universes, far more cycles...