I saw something on all this earlier today.
Google announces privacy changes across products; users can’t opt out
http://www.washingtonpost.com/business/technology/google-tracks-consumers-across-products-users-cant-opt-out/2012/01/24/gIQArgJHOQ_story.html
Seems to be planned for March.
However, yesterday I spent some time looking for an odd item, something that would help me to reach the middle of my back with lotion, as I have dry skin, an all year condition for me in New Mexico, land of sand. I had an idea of something I could rig up that could work, and tried it and it did work, but in the meantime, I looked at sites about loofahs, Amazon and one other, thinking loofah with a handle, that maybe I could wrap or use as is. Turns out, should you be interested, there's tons of stuff out there for this, undoubtedly available at beauty supply places that I never frequent.
So... this morning, I think when I was checking the LA Times or possibly some other website, what do I get but a fat set of ads for loofahs and lotion rollers.
Sooooooo, unless that was a magical coincidence, they're already tracking via sites I go to, not just ads I look at.
Edit - I've just noticed some headlines out there that there is a big backlash about this.
So far I'm not too worried, since I'm a middle aged male who searches out loofahs.