After reading that description of the claims of the lawsuit it sounds like an open-and-shut case.
I imagine it's going to hang on the "caused harm" aspect of defamation. Can the fraternity prove its members were harmed by this story? Denied jobs, ostracized, etc? I suspect they have a very good case, but the fact that none of them are named will be interesting.
Seems unlikely it ever gets to trial. I'm still curious if what Richard Bradley suspects turned out to be true, that Rolling Stone's lawyers had major objections to the piece and RS went ahead with it anyway. I suppose that's still protected, though, and unlikely to come out at trial, although it would be interesting if Dana and Woods were asked that specific question and chose not to answer.