Logging out doesn't necessarily disable the tracking, though, as the cookies are still there. You could delete them, but I bet the like buttons reset new ones, which correlates your history to you the next time you log back in.
Much better is to just nullroute their netblocks at your router. That's what I do.
I do the same thing, and it really doesn't take much. I've been blocking 3rd party cookies for over a year now, and the only one I had to add was rememberthemilk, so that I could include my TODO list in a GMail widget.
It's pretty simple, really: Edit Preferences -> Privacy -> "Firefox will: Use custom settings for history" -> <uncheck> Accept third-party cookies. To add an exception, click "Exceptions..." on that same page, type the domain name, and click Allow.
You can still receive normal cookies, but now third-party sites can't track you unless the sites you're visiting are sharing data server-side.
Poster may be referring to the phone address book scandal, probably only one example. In that case importing your facebook contacts from your phone grabbed your entire address book, with what looked like account placeholders for anyone in your phone that wasn't already on facebook. Oh, and it published all their phone numbers too.
I'm sure facebook has myriad nefarious ways for tracking everyone you interact with regardless whether they have an account.
And do we need to point out Double click got caught tracking individual users and lying about it over 10 years ago.
Some sources would obviously be helpful, but I don't think anyone is kidding themselves about what's going on.
It was a blog post I can't find right now, but it's easy enough to reproduce: I deleted all the cookies from Facebook and then open a tab to a site with the Like button. A cookie for facebook.com is created called "datr" with an obvious ID and an expire date two years from now.