Ironic. Amazon.com, recently (and you have to believe, reluctantly) gave in to the Authors Guild over the Kindle 2's "Read-to-Me" feature. In that case the Authors Guild wanted restrictions placed on that text-to-speech feature. Now Amazon.com is ensuring it can restrict where you can buy e-books for your Kindle.
Yes, buy, not download illegally, but buy.
The site MobileRead was sent a DMCA takedown notice for a link to a Python script which would deriver a Mobipocket-compatible personal identifier (PID) for your Kindle. This would then allow you to shop at Mobipocket-format ebook sites.
Oh, the horror. In reality, this has nothing to do with copyright infringement, but instead with restricting Kindle users to buying content solely from Amazon.com.
It's also of note that it was discovered way back in 2007 that Amazon's AZW files are actually Mobi files, but since Amazon didn't share Kindle's Mobi PID, which would allow one to buy encrypted Mobi books for Kindle, users were stuck, until the development of the Python script, kindlepid.py.
It's not like one could Google and find the link to kindlepid.py, or even worse, a way to remove the DRM from AZW files, could you?
Now that, I could see Amazon.com having a legal leg to stand on, but the other script, which just made it possible to legally buy and read ebooks from other stores? While I can understand why ($$$), that doesn't reduce its lameness.