Doesn't answer the exact question, but here is some of Kobo's policy:
http://blog.kobobooks.com/2010/10/22...open-platform/
Here's an excerpt:
Rest assured that Kobo safely backs up and stores all your books in one central location, regardless of where you registered, where you purchased your books, or what device you’re using (computer, eReader, Blackberry, iPhone or iPad). Your books will follow you wherever you go, without needing a trail of breadcrumbs (virtual or otherwise) to find your way back.