Breaking promises information would not be shared without users' consent, Facebook, MySpace and other social networking sites have been sending user data to advertising companies. This information can be mined for names and other personal information, the Wall Street Journal reported today.

In sending the information to ad companies, the social networks gave user names or ID numbers that are linked to personal profiles being viewed when users clicked on ads. "After questions were raised by The Wall Street Journal, Facebook and MySpace moved to make changes. By Thursday morning Facebook had rewritten some of the offending computer code," the article stated.

Other than Facebook and MySpace, the other offending sites were Xanga, Digg, LiveJournal and Hi5.

"If you are looking at your profile page and you click on an ad, you are telling that advertiser who you are," Ben Edelman, assistant professor at Harvard Business School who studies online advertising, explained to the Journal about how Facebook operated before the fix. He was asked to look at the code on the seven sites on behalf of the Journal.

The WSJ's report jumps off a study from last year, in which two computer scientists from AT&T and Worcester Polytechnic Institute studied the types of information sent to ad networks from Facebook, MySpace and other social networking sites, MediaPost reported last September.

Leaking what users consider to be private information isn't a new problem, but because users share so much personal information on social networking sites, this case is a bigger problem, Jules Polonetsky, co-chairman and director of the Future of Privacy Forum, told MediaPost.

Today, Facebook confirmed it will change its privacy policies in order to make them easier to understand for users, PCMag.com reported.

"Much of this, is bad behavior from Facebook, but we doubt it'll get punished for it. Right or wrong, we don't think Facebook users care about these kinds of issues enough to quit Facebook over them," Business Insider noted.