The future of Mobipocket (as a site and as a format) and the future of DRM are somewhat connected.
With the decline of prc in favor of epub we experience the first major eBook store and one of the most popular eBook formats to gradually vanish and lose significance. Should Mobipocket.com ever close its doors, no other major eBook store will mainly support prc.
As one format among others, of course. But will shops still stick to DRM prc then? More, will customers even WANT to rely on DRM prc?
Should Mobipocket.com ever have to close, Amazon loses its major asset to capitalize on prc, especially on DRM prc. The exclusivity clause simply would become irrelevant then. As long as there are non-e-Ink devices out there , there's a market for DRM prc, but it will steadily decrease.
There's quite some lessons to be learned from this "casus DRM prc" in the months to come, and I do hope that shops, publishers and manufacturers are willing to look closely and avoid any unfortunate decisions in the future.