Anybody who trusts Facebook to care about your privacy is completely ignorant. You can use Facebook safely, but only if you check your security settings regularly, turn off all third-party apps and ignore all third-party apps in your news display.
This site strategically acquires posted content and personally identifying information for its own use, or in the sale of targeted advertising. Read the privacy statement, and be aware of its contents and the rights Facebook has over you.
For example, Facebook has the right to do what they wish with any content or information you post *by default*, as your use is your consent. You must take specific action, such as opting out of third party advertising, to limit their use of this information. Be aware that doing so will not grant legal protection, nor will it stop targeted advertising, only decrease its effectiveness.
Other action includes carefully examining the other privacy or security settings on your account, and ascertaining that these settings are arranged to your preference; again, these are set to the least private by default, as it is on most sites, such as Youtube, Google, Hulu, etc.
People can very easily create fake profiles, message you saying their an old friend, they give you a link to their "real facebook page", but by simply clicking that link, all of your cookies, passwords, etc. is now readable by the third party phisher.
03/02/2011: NOT HTTPS! Make sure you fail a log in before putting in your info to get to a secure page.
02/04/2011: People tend to invite you to applications that would make anyone with a picogram of tech experience person ask, WHY?
I guess not enough people have MyWot / SiteAdvisor.
Shame, a full decade later and people are just as ignorant as they were back then!