Okay, you uploaded your ebook to Amazon or Smashwords. You've sold a few copies.
And now ... you're wishing you could autograph your ebook just like a real book.
You can! You can send a personalized inscription/note and your signature to your readers. All you need to do is set up an account at Kinglegraph. Then, you can offer your readers this personalized service.
Go to Kindlegraph to watch a screencast about the service.
Note: You must have a Twitter account to set up a Kindlegraph account.
A tip of the fedora to Marian Allen for pointing Panzer to this service.