When Facebook was in it's infancy, they were desperate to get as many users as possible.
To do that, they had very few rules. Their TOS, terms of service allowed things that they no longer allow.
To get a Facebook account, you have to agree to their TOS.
HOWEVER, whenever they change their TOS, that voids the previous TOS, and users must AGREE to the NEW TOS.
Where in life can you have a contract or agreement.. that one side changes in the future without the consent of the other party?
Also, Facebook has rules against virtually everything. They selectively enforce these rules when they want to eliminate someone.
Beyond all that.. they also have done things which are illegal - such as asking for FULL social security numbers. Only government institutions and financial institutions have the right to even request that information. I personally have gotten email from Facebook demanding my social security number as a form of identification.
If anybody doesn't believe that Facebook makes a fortune out of selling it's user's personal information to government agencies, telemarketers, investigation services, and advertisers, then that person is ignorant and naive.
How many users to you think Facebook would have if they clearly informed it's users that "we may sell your personal information to government agencies, telemarketers, investigation services, and advertisers"?