The internet is for a lot of things. A social network is for socializing. Fan sites or pages are a form of socializing. Certainly Facebook is within their righ

The internet is for a lot of things. A social network is for socializing. Fan sites or pages are a form of socializing. Certainly Facebook is within their rights to prohibit this kind of thing. You can even see why they'd want to do it: to make Facebook more friendly to the paying customers (advertisers). But it's an interesting question, how far down this road Facebook or any other site can travel before the utility of the site is reduced to the point that there aren't enough active users to attract paying customers.