Their concept sounds fun and very targeted, even though i couldn’t use it since i am no Mac user.
Here’s how they describe themselves:
iCompositions.com is an internet community for aspiring musicians with a focus on Mac-using artists and, even more specifically, users of Apple’s GarageBand. Artists can upload an unlimited number of songs to be played and critiqued by other members of the community. We strive to facilitate the exchange of constructive criticism to give each artist the opportunity to improve and enjoy their musical adventures.
So, if you’re Mac user here’s Icomposition site for you so you can give it a try.