I see the problem. Your username is a way for people to identify you on the site. Usernames are unique. For example my profile would be on http://singleforest.

I see the problem. Your username is a way for people to identify you on the site. Usernames are unique. For example my profile would be on http://singleforest.com/users/epochwolf http://singleforest.com/users/epochwolf and all comments I make would have my username (epochwolf) on them. I can definitely make this more clear on the registration pages.