I don't remember seeing this before at the bottom of the Craigslist posting form. I'm guessing this is the result of the Padmapper debacle? (bolding mine)
Clicking "Continue" confirms that craigslist is the exclusive licensee of this content, with the exclusive right to enforce copyrights against anyone copying, republishing, distributing or preparing derivative works without its consent.
For comparison, here's Yelp's language:
As such, you hereby irrevocably grant us world-wide, non-exclusive, royalty-free, sublicensable, transferable rights to use Your Content for any purpose.And Facebook's:
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 FacebookGoogle:
When you upload or otherwise submit content to our Services, you give Google (and those we work with) a worldwide license to use, host, store, reproduce, modify, create derivative works, communicate, publish, publicly perform, publicly display and distribute such content.