I'm glad this came up to make me think about it more; I'd already gotten in the habit of logging out of FB except when actively viewing the feed, for precisely this reason---I didn't want FB tracking me across browsing other sites. (The FB-hosted comment systems were actually the proximate worry, as well as the Like button.) But that was my half-thought-through answer. Of course they're perfectly able to track me eve…
I used to do that. I also started deleting any Facebook cookies before logging into Facebook, and after logging out of Facebook. I then realized that was stupid, because I have a static IP address (helps with my job, which requires remotely logging into servers). With Facebook cookies everywhere, you don't need to be logged in for them to track you. And in my case, even if I used a different browser for logging into…
You should be able to remove that from your ad targeting here: http://www.google.com/ads/preferences/ It lists all the categories Google thinks you're interested in and allows you to add or remove categories.