That's true, but at the same time it would make a world of difference depending on your service. I asked the question because our app Persona is like an about me Page, in pictures. Most of the requests I'm getting is because people like Paul or Bob, Tim etc want to have their personalized URL linked with our app. Imagine if you were a Paul and you were sending your friends a link: http://www.prsna.me/paul . The appeal there for a less than 5 character username would then be justified as I see it.