From the new terms of use of Facebook:
You hereby grant Facebook an irrevocable, perpetual, non-exclusive, transferable, fully paid, worldwide license (with the right to sublicense) to (a) use, copy, publish, stream, store, retain, publicly perform or display, transmit, scan, reformat, modify, edit, frame, translate, excerpt, adapt, create derivative works and distribute (through multiple tiers), any User Content you (i) Post on or in connection with the Facebook Service or the promotion thereof subject only to your privacy settings or (ii) enable a user to Post, including by offering a Share Link on your website and (b) to use your name, likeness and image for any purpose, including commercial or advertising, each of (a) and (b) on or in connection with the Facebook Service or the promotion thereof.
Via ALT1040.
Update:
Mark Zuckerberg has clarified the reasons for the new legal terms on sharing content in Facebook:
Our philosophy is that people own their information and control who they share it with. When a person shares information on Facebook, they first need to grant Facebook a license to use that information so that we can show it to the other people they’ve asked us to share it with. Without this license, we couldn’t help people share that information.
Read the full post here:
http://blog.facebook.com/blog.php?post=54434097130