Ok, this is just getting silly and pointless.
Other posters have already pointed out the factual inaccuracies in the summary (e.g. Leaving Google+ affects your other Google services - no it doesn't, etc.).
However, all these whiney privacy screaming privacy advocates are ignoring one very important fact of life - nobody cares.
In your pathetic, mundane, meaningless life, who (God aside) actually cares? I myself will readily admit I'm a boring person. I mean, sure, I care about my hobbies, my friends, my faith, my likes/dislikes. But seriously, you thing some mindless drone in Mountain View cares? Or somebody halfway around the world?
Unless your name happens to be Barack Obama, or heaven forbid, Lady Gaga (or whatever her real name is, frankly I can't even be bothered to Google it), I doubt anybody outside your circle of friends or families would actually take five minutes out of their day to read up about it.
Nobody is going to stalk you buddy, sorry. Please. Don't be so conceited. There's no global conspiracy with people shadowing your every move. Worst case, some guy is going to try and sell you a breakfast cereal cause the algorithm tells him you like breakfast cereal. Big frigging whoop.
I mean, jeez, do you have a Wikipedia page? Are you of note? Pftt. I'm certainly not.
Heck, if they can make ads more targetted, so I don't have to sit through ads selling me useless c*ap I wouldn't need (e.g. swimming lesson, or hair dye, or woman's products), I'm all for it.
And for a tech-oriented site, people here are surprisingly un-tech savvy.
Do you really think some intern is sitting there look at the sites you visited? There are probably 3.1 billion people out there more interesting than you. It's an *algorithm*, alright. They put in a couple petabytes of data, and it spits out gross aggregated trends. I doubt they even have the capability of picking out a single person, let alone any reason to pick you. Heck, if they picked somebody at random every day of the year, it'll be the heat death of the universe before they pick you.
Look, the only people that care to stalk me, or pillage my personal data are probably friends, family or somebody I have some kind of relationship with. If I had a friend at Google with access to that data, sure, I might be worried. Lol. But I suspect very few people have access to that data. It's not exactly like they'll publish it on the company intranet.
One of my parents works for a financial institution. They told me that one of their colleague was dismissed for opening up a friend's file at the bank, just for curiosity. Companies aren't idiot. They do understand things like need-to-know-basis, and audit trail.