I recently got a new phone and glanced at the Facebook EULA when I was installing its app. It's pretty horrific as they claim an irrevocable license to whatever I post.

"
Sharing Your Content and Information

You own all of the content and information you post on Facebook, and you can control how it is shared through your privacy and application settings. In addition:

1. For content that is covered by intellectual property rights, like photos and videos ("IP content"), you specifically give us the following permission, subject to your privacy and application settings: you grant us a non-exclusive, transferable, sub-licensable, royalty-free, worldwide license to use any IP content that you post on or in connection with Facebook ("IP License"). This IP License ends when you delete your IP content or your account unless your content has been shared with others, and they have not deleted it.
"

The crazy part here is that last little bit - the content will remain on the network so long as everybody you shared it with doesn't click the "delete" button on it. Has anyone ever seen such a "delete" button for other peoples' content?