FB wants to change their data management policy in a way that would strip you of your ownership of all data uploaded to the site. That's against prevailing data protection laws and hints at ulterior motives. Why want they total ownership of our personal information? Who want they sell it to?

If you're on FB and don't agree with that, follow the steps described here and challenge the switch.

It's because that's one of the ways FB gets money from. selling information about their users to companies so companies can see what the users like and don't like so companies can adjust themselves to sell stuff the users might like. Same thing goes for Orkut.
random example: X% amount of people have pets, FB sells this information and companies work harder in selling pet prooducts.

Yeah, advertisement revenue is one of their biggest money sources, but that's something different here.

By making themselves the owners of your data they not only infringe governing privacy laws, it hints towards underhanded business practices. Spammers are advertisers, too, and let's say a user sues FB for selling his data to the spammers after his personal website broke down under the onslaught of bot-generated spam comments, they could just point out that they can do whatever they want with your data since you didn't own them from the moment onwards you first uploaded them to FB. "Didn't you read the fine print?"

Ditto if you want to sue them for forwarding data to the NSA or whatever under CISPA even though you aren't even a US citizen.

Facebook is the Evil.

I don't have an account on Facebook or Twitter.

I have never wanted one and don't plan on having one for reasons like this. Your personal information is just at too much risk.

And it's OVER 9000!

To be honest for those smart people that join FaceBook, they'll only get your email address, your birthday, your fake age, your fake location and school and place of business, and your name.

There's not really much of mine they have.