Why not make people register? It takes all of 5 minutes or so to register. How easy is it to create an identity here?
hmmmmm...
Let's see go to hotmail, yahoo or some other place that offers free email, sign up for a free email account.
Come to pm and register.
I know people say they will get crushed with spam by registering, I don't know if this used to be true, however, I don't think I have ever recieved a bit of email from perlmonks since I joined. I think that if people feel like they belong, they are more likely take some responsibility for their postings. I also think they may start feeling their way around the monestary and learning what it has to offer. This will not help with trolls, as they can do the same things, but as a member, they may just post the @^$#$@ questions that every one always gripes about in the CB rather than creating a root node that is just noise.

Speaking as someone that has jumped the gun and posted those $#$%%# questions that annoy everyone before searching%^)