As part of our ongoing initiative to streamline the user experience, OverDrive has ended support for the Mobipocket eBook format which means that this format is no longer available for selection in Content Reserve. For libraries with Mobipocket eBook collections, OverDrive will replace any copies with a corresponding number of units for use with Kindle or other supported reading devices. There will be a very small number of titles that we are unable to replace with other formats. For those libraries affected, we will contact you separately with a report of these titles and issue a full content credit for amounts paid for those titles.
What's most interesting about this is not that they are killing off Mobipocket, but that Mobipocket ebooks still show up when you search via OverDrive's website. Of course, when you click through on any of the book listings you won't see Mobipocket as an option, just whatever format that OverDrive offered as a replacement.
Amazon bought Mobipocket in 2005, and kept it around just long enough to create the Kindle. Ever since then Amazon have been slowly killing off Mobipocket, first by swallowing the existing content into the closed Kindle system (cutting off existing retailers), then blocking new app releases (there was supposed to be a Mobi iPhone app in 2008), cutting support, and now this. No,it's not a coincidence that Kindle support was added at the same time that Mobipocket support disappeared.
Pity. Much of Mobipocket's services may live on under the Kindle name, but that doesn't mean much to the early adopters that Amazon threw away. I know that a company will always act in their own best interest, but Amazon's cavalier attitude toward existing customers should worry you. They'll do it again if it serves their interest.