If you want your students to all have usernames on a blog or a wiki or something like this, it’s a good idea to generate them yourself. I learned this the hard one, when in one instance I was using a forum, and I let the students create their own usernames, one of them actually impersonated me (my username was RobertBorgersen, theirs was Robert_Borgersen). They had done it as a joke (that ended up being pretty harmless), but still. Things could go really wrong really fast.
So, one good way to go is to assign them usernames. Now, you could use their real names, but that kills annonymity, and may make them more scared to answer questions. So, if you’re going to make up usernames for everyone, why not make up some cool ones that they will like?
Check out http://www.voidstate.com/name_generator/. This is a name generator, used primarily by geeks (like me) to generate names for characters for playing roll playing games. However, these names are quite good for the purposes I described here! Here are some sample names I generated in 5 minutes of work:
Of course I would be happy to replace a student’s username if they don’t like it, but at least I have a place to get them so I don’t have to come up with them myself!