EDIT: I should have done more than exclaim. I can understand where this clause is coming from. Amazon does not want business partners giving other stores exclusives (even though they just did that with some Android games). This is their Level Playing Field Clause. A similar thing happens with eBooks and pricing. If Amazon finds your book for less on another store, they will price match it or even price it for less. They can't, of course, pull a clause like the above with eBook publishers because Kindle is not a universal file format. I'd say you'd have to terminate the agreement to get out of it. IANAL, again.