brotherhood_of_LAN - 2:00 am on Jan 7, 2013 (gmt 0)

The only reason I can think of this even mattering is that underscores are usually treated as a 'word character' in regular expressions. That and perhaps usernames tend to have underscores too, which are fairly prevalent entities online....

Can't help but smile a little, after all the web's technological advancement, this question is still one that matters. fwiw I don't think it's a big deal anymore but maybe it's one of those tiny edges that you can gain on competition.