Those who doubted that an exclusive license was truly exclusive should take note.

Craigslist here is arguing that they own essentially full copyright on all listings. This means if you advertise on Craigslist and you submit the same listing somewhere else you are guilty of breach of contract, and the other party may be guilty of copyright violation. How long before users start getting sued by one party to such litigation?

This is big trouble. We need to highlight that you give away all rights to all issue listings including the same material elsewhere.