Frankly I am comfortable with the idea that a site might own the personal information I post on their area. When I update my Facebook account, I am aware that I am sending information to the 200+ friends I have listed. I realize they can write back, forward and copy and paste that information. This is the duality of social media: You're doing something private in a very public space. It's best to be aware of this and get used to it as the way things are and will be as the Web evolves. I don't think one would even need to wait for Facebook to aggregate data or cull through profile areas. Your friends could very well be spreading your information - online and offline. Post with 'this' in mind.
This is not Facebook's first attempt (or incident) trying to make use of the tremendous amount of user data that accumulates on the site. Facebook is looking for another way to make money from the site besides advertising. It's sitting on a gold mine. If users would understand the full set of ramifications of how their information would/could be used and opted-in to share or sell their information, then there would be new business models emerging from social networks.
Take a look at this interview between SAP's Steve Mann and Prof. Sinan Aral from MIT and NYU. Aral makes the very good point that understanding audience's demographic profiles is not enough. Companies can be a lot more effective in their communications if they understand their audiences' networks. In other words, who you know, where and how you know them gives marketers better information about you then just your age, gender and location.
There is an old saying in Turkish: 'Tell me who your friends are and I'll tell you who you are.' I guess it boils down to that.