I had a rather amusing conversation with my coworker today about this. I think that companies should not collect that kind of data, despite the benefit in terms

I had a rather amusing conversation with my coworker today about this. I think that companies should not collect that kind of data, despite the benefit in terms of improved products (personalized search, ads that don't suck, whatever), whereas his basic attitude was "I'm not doing anything illegal, they're not doing anything illegal, so why not?" While I would not mind being shown ads I care about, I worry about the cost. I don't want companies to be able to share detailed click trails and be able to produce in depth biographies because of the potential for abuse, be it governmental, corporate or "hm I wonder what I can find out about that girl I met yesterday". PS: as an addendum, I know people with Google log access, and while it's less scary than it sounds, I know there are "tons" of people with such access... and counterparts at other companies. I don't know if I can trust all those people with knowing when I get funny rashes or whatever.