A tale of 11 downloads after one day in the #6 spot for your category in the Mac App Store. Those are some surprisingly low sales numbers. I would say that part of this is aided by the fact that it is an odd app that most can’t use, but it passed things like BBEdit and Coda.
This leaves me to think that Apple’s algorithm is not what most think it is for determining rank. My bet is that when you have a sudden surge of downloads (relative to your app), you start moving up in anticipation of more downloads.
Still, 11 sales seems pretty low.