How do you sign an e-book?

This was a blog post from Daniel Pink that I had not thought about before:

http://www.danpink.com/archives/2011/10/how-do-you-sign-an-e-book


It is called the Kindlegraph

• Log in with your twitter account
• Look for your book you want autographed
• Request a "Kindlegraph" from the author
• They use their finger or a track pad to make their signature
• Then send it to your e-book