They are covered in the TOS/EULA, but based on some of things that have happened so far and some of the things written about it, it's far from clear that this stuff would hold up in court. You might think it should, and I think it should, but who knows if a judge would agree:

http://www.jdsupra.com/legalnews/an-update-on-the-legal-impl...

http://www.buzzfeed.com/jwherrman/want-to-publish-a-twitter-... -

https://pando.com/2013/01/22/how-twitters-new-embeds-will-ma...

Clear as mud.