Boom Recorder appears to be dead and buried. Rather sad. (if you don't know Boom Recorder, it was a dedicated live audio recording application for the Mac).
Apparently, it's not working with Snow Leopard, and development has ceased, so it's been removed from the store - you can no longer purchase it.
That's a real shame, although not too huge a surprise since it feels like there hadn't been a new version in years. But it was a clever app with some very clever features, and with a little more development I felt it could have been the perfect live tracking software.
Come on Presonus, help us out here. We need that proper hardware-independent multitrack version of this:
PreSonus