A while back, a girl made a Facebook page accusing a guy at her school of being a rapist.
A longer while back, the website Girl Don't Date Him was used not to post pictures of pink bras on large boobs or as a place to house articles (pink ones) about cheating men, but as a place where women could post stories, pictures, and full names of their terrible exes, as a sort of "we're in it together, sisters" warning to other women.
Legitimate guerrilla warfare against injustice, or terrible idea for a million possible reasons? Well, my answer depends partially on whether or not the accusations are true. If a guy gets drunk and turns into a violent psychopath and sprains his girlfriend's wrists and leaves her unable to walk for days and makes her fear for her life, I think he deserves to be called every goddamn name in the book, in public, with everyone imaginable given access to it and made to read it. I think he deserves to pay for his motherfucking terrible actions in all ways possible.
But if I don't know the victim, and I therefore have no reason to believe that either person is lying or telling the truth, I might respond with something like, "Well, this is a very bad idea. It could hurt the victim in court [in the case of rape, domestic assault/abuse, etc.], it could cause hostility toward the accused, who hasn't been convicted of a crime. And also, that's probably illegal in some way or another, as well it should be, if you can imagine being the 'asshole outed on the internet' who is actually innocent. The very nature of such a thing harms the spirit of "innocent until proven guilty."
But when I know the victim, that less vindictive, more rational, more practical side isn't very loud. And then, I only wish I knew how to make a kickass website that everyone would read with pictures and links and addresses and phone numbers and directions to houses.