The following came in an email from The Authors Guild in response to the Amazon/Macmillan feud.
The Authors Guild is pleased to announce the launch of WhoMovedMyBuyButton.com, which is now live in fully-functional beta form. Who Moved My Buy Button? allows authors to keep track of whether Amazon has removed the "buy buttons" from any of their books.
Simply register the ISBNs of any books you'd like monitored, and our web tool will check daily to make sure your buy buttons are safe and sound. If there's a problem, we'll e-mail you an alert.
Although we've launched WhoMovedMyBuyButton.com in response to Amazon's wholesale removal of buy buttons from Macmillan titles, we believe Amazon should be monitored for years to come. Amazon's developed quite a fondness for employing this draconian tactic (there's a chronology at the website); it's only grown bolder with its growing market clout.
Vigilance is called for: sounding off is our best collective defense. Register your ISBNs today -- it's free and open to all authors, Guild members and not.
You can find other thoughts on the subject here:
Amazon Pulls Macmillan Books Over E-Book Price Disagreement by Brad Stone (The New York Times)
John Sargent addresses all Macmillan authors and illustrators
Why My Books Are No Longer For Sale Via Amazon by Tobias Buckell
Macmillan Books Gone Missing from Amazon by John Scalzi
AmazonFail, Part 2? by Laura Anne Gilman
The Macmillan vs. Amazon Throwdown by Susan Piver
quick sketch on the Amazon vs. Macmillan weekend theater by Jennifer Jackson
Amazon.com mysteriously removes Macmillan book titles by Paul Boutin
...and a bazillion others by searching 'Amazon vs. Macmillan'