Someone else may have already made these points but:
- libraries won't have to choose sides in the format war. they license titles, and Overdrive will supply either ePub or Kindle format (virtually all of the ePub titles libraries currently purchase are also in Kindle format). There might be a few cases where there isn't format overlap but obviously all parties will work to close that gap.
- obviously the already-skyrocketing demand for ebooks will spike when Kindle format becomes available. Hopefully some of this will be mitigated by people who already own both Kindle and an ePub reading device like myself and who will simply have a choice of formats where before there was none. But Amazon or not, we were already well on the way to long wait lists.
- I am very curious how it will work technically. The Amazon announcement says there will be synching support. That implies a checked-out book can be read on any device linked to your Amazon account. At what point do you have to supply your Amazon credentials, and to whose server? When do you identify the device you'll be reading on? Whose server actually fulfills the download? Presumably you have to somehow link your library and Amazon accounts somehow or this won't work. They must have worked out a way of (hopefully securely) sharing these credentials. Finally is it gonna be whispernet? or will you need to tether to a computer?