Ah, but that just changed a week or so ago.
If you e-mail an e-book that is compatible with the Kindle (e.g. mobi, azw) to your device's Kindle e-mail address (
[email protected]),
Amazon now will put that book into your Personal Documents AND into the archive. Then, you can use whispersync, annotations, etc. to your heart's content (well, with all but PDFs).
See this
Amazon help page for details:
Amazon.com Help: Kindle Personal Documents Service, but here's the money quote (my emphasis added):
And, I can tell you from personal experience that this works. I've e-mailed 200+ books I have from other places (Smashwords, Baen, Google, Mobileread, etc) to my Kindle. When I open the book and read for a bit, then open the same book on my iPhone or the iPad - I am offered the chance to go to the furthest read point, just as if I had purchased the book from
Amazon.
Yes, it's a bit of a pain, e-mailing all those books. But, it only has to be done once (and
Amazon will store up to 5GB of data in your personal documents file).
Awesome!
So awesome, in fact, that it's the reason I now HAVE a Kindle (just got it this Thursday past!). I prefer to read with an e-ink device, but I'm harsh on them out of the house (have broken 3). This way, I can read with my iPad/iPhone while out of the house, then, when I get home, I can pick up the Kindle and resume where I left off.
But, that's my personal problem (and probably more than you care to hear).
So, give it a try. As I said, it works great for me - maybe it'll work for you.
Marilyn