I think this (Double your price! (and no, I'm not kidding) - http://tinyurl.com/3xcounq)
is a must read for you, particularly concerning the MD versions of your app.
Ironically, you can read an argument against shorteners on this same blog here-- http://jacquesmattheij.com/Down+with+URL+shorteners
Note: I avoid shortened links like the plague, just an interesting observation.