I just tried out the new PrivacyFix extension, which checks your privacy settings and also estimates how much Facebook and Google make off me each year.
Turns out, my privacy settings are pretty decent already. And, it looks like Google makes less than a dollar per year off me. Facebook makes nothing. The guy that wrote the article on Ars Technica clocks in at $700 per year going to Google, through advertising etc... Wow.
I'm running PrivacyFix, in addition to Ghostery and AdBlock, on all computers that I use.