So I'm attending grad school, and use an HTC Flyer to purchase my textbooks through Amazon's Kindle. I have the Kindle software on my Flyer, my Mac, and the Cloud Reader installed in Chrome on my Mac.
I went to class this evening, and took my laptop instead of my tablet as I had some coding to do which I wanted to get done before class. When class time came, I opened my Mac Kindle software, and attempted to open my book for class. The software told me that the book couldn't be opened, and that I should re-download it. I did that, and got the same error message.
I tried to open it in the Kindle Cloud Reader, and that's when I found out that I couldn't read it there either, because "The number of licenses for this book has been reached. Please deactivate it on another device if you wish to use it here." That meant, of course, that I couldn't read the book in class; without the tablet, I couldn't de-authorise it on there, and I couldn't open it on my Mac. Thankfully, a classmate shared her book with me for the instances where it was necessary.
However, what galls me is that I should have been able to open the book on my Mac. There's no reason why, when I purchased the book legitimately (for $56.47), that I can't read it on all the devices that I might use. Now, in order to be able to use the book I legitimately bought I'll have to find a software that would remove the DRM. If I choose to use it, I would technically be breaking the law, making me (in effect) a criminal. While I wouldn't expect prosecution (especially since I haven't actually done it), it's a ridiculous thing that DRM makes criminals out of legitimate purchasers. This makes me less inclined to make legitimate purchases, and more inclined to try and find pirated copies of textbooks in the first place. After all, a pirated copy wouldn't have all these issues! If I'm going to be a criminal no matter what happens, I might as well save the $56.47. This is how the "protection" that's supposed to protect writers actually ends up hurting them, and makes criminals out of legitimate users.