Do you set a max length to the username someone can register with? What is it and why? Also,if you use a regex for username standardization, what is it and is there a reason for it besides the looks? With my current site style, 15 characters is causing the username to overflow to another line and my dilemma is whether to slightly redesign and/or limit the username size so that it does not go over. Update: After analyzing a forum with a little more then 18k users (and never had a username limit), here are the stats for username length of current users. 21-25 characters: ~ 30 Users ( About 10 actually posted at least once) 16-20 characters: ~ 200 Users(About 50 actually posted at least once) 15 characters: ~800 Users 11-14 characters: ~6.5k Users 1-10 characters: ~ 11k Users With that in mind, there is no need to allow over the 15 char length (in the case of the forum analysed).