Facebook is the world's biggest social networkingsite．People are being tricked into Facebook with the promise of a fun，freeservice without realizing they're paying for it by giving up loads of personal information．

Most Facebook users don't realize this is happening．Even if they know what the company is up to，they still have no idea what they're paying for Facebook because people don't really know what their personal data is worth．

The biggest problem，however，is that the company keeps changing the rules．Early you could keep everything private．That was the greatthing about Facebook-You could create your own little private network．Last year，the company changed its privacy rules so that many things-your city，your photo，your friends'names-were set，by default （默认），to be shared with everyone on the Internet．

According to Facebook's vice-president Elliot Schrage，the company is simply making changes to improve its service，and if people don't share information，they have a"less satisfying experience"．

Some critics（批评家） think this is more about Facebook looking to make more money．In original business model，which involved selling ads and putting them in the side of the pages totally，who wants to look at ads when they're online connecting with their friends？

The privacy issue has already landed Facebook in hot water in Washington．In April，Senator Charles Schumer called on Facebook to change its privacy policy．He also urged（催促） the Federal Trade Commission to set guidelines for social networking sites．"I think the senator rightly communicated that we had not been clear about what the new products were and how people could choose to use them or not to use them，"Schrage admits．

I suspect that whatever Facebook has done so far to invade our privacy，it's only the beginning，which is why I'm considering cancelling（取消）my account．Facebook is a handy site，but I'm upset by the idea that my information is in the