Nothing is being "analyzed" -- it's a free service from Google for website owners to let them know how their users use their site so they can have more germane ads and stuff. There's nothing personal at all, it's more a statistical sort of thing so websites can be made more useful to users. Individual ads aren't chosen, they come from who goes where and clicks what on the site (not just "members" in the forums but throughout the whole, huge site, visitors and anyone coming to the site anywhere) so if a lot of people come through the RSS feeds and click on/read an article on depression, for example, there might be more depression med ads for awhile, that sort of thing. It's just to draw more people to the entire site by knowing what the "majority" like/are reading. Then the site can offer more stuff like that and since the ads will be targeted more toward what those people are reading, hopefully more people will click the ads which will make the site more money so it can improve, etc.