It depends what you were browsing when it picked up your interests and who is watching when it shows the ads! A UK ISP got into trouble when it was (illegally)

It depends what you were browsing when it picked up your interests and who is watching when it shows the ads! A UK ISP got into trouble when it was (illegally) tracking all your web browsing and replacing each site's ads with it's own ads based on your browsing history. When it replaced the ads for a childrens charity on a national fundraising event with some targeted at 'gentlemen's special interest' sites there was something of an outcry