Facebook plans to use this information to improve its services and its targeted ads. That's all well and good, but is anyone else getting mad 'Big Brother' vibes from this news?
At this point, Facebook is already almost psychic with the information it has on users. A study done by Cornell University (“A Network Analysis of Relationship Status on Facebook”) showed how Facebook can pretty much predict who your boy/girlfriend is, regardless of whether its 'FB official' or not. Based on the number of mutual friends you share, the site can then reasonably predict whether the relationship will last longer than 60 days. Why they would predict such a thing? God and Zuckerberg only know.
Combine this creepy information along with the 200 trackers (a 'request' to track, record, and share online activity) Facebook already has on your internet activity, it looks like FB will be changing its name to SkyNet soon. That was a Terminator reference for all the non-nerds out there. Movie references aside, Facebook can literally track nearly everything you do online, so be wary friends, Facebook is always watching.