Good point, we'll switch this soon. The current code base is more for proof of concept purposes. We were also concerned with having easy ids to send others. We'll get on this!
http://stackoverflow.com/questions/367586/generating-random-...
It'd be nice to be able to say "Keep track of my progress at http://mobileply.com/matt or something similar. Heck, I could see myself even paying a couple bucks for a nice url like that.