I have a couple alt-nics that I use. I used to do all of the news posts but I decided that we needed a real news guy so "TheNewsGuy" was born. I even gave him his own forum. He reports industry news and always adds a bit of commentary (opinion) that I wouldn't normally get away with.
I don't try to mislead anyone with these nics, I just use them to add a bit of flavor and variation to the boards. I think it can be a great idea. I have to agree that a couple phantom users in a chit-chat forum can be a great idea too. sometimes all it takes is a small amount of activity to get the others rolling. Don't be afraid to post information even if your last post hasn't been replied to. carry on like everyones watching and have a good time while you're doing it.