As has been reported in on Lilliputing, TechCruch, Goodereader, and several other places, Gigaom has a screen shot of an Amazon page that appears to be introducing KindleUnlimited, an all you can read book program for $9.99 a month. This is similar to other services like Oyster and Scribd, but Amazon is by far the largest player in the ebook market.
According to the screen shot, more than 600,000 books and just over 7000 audiobooks would be available.
There has not been any response from Amazon publicly yet. But unless someone is having fun with a mockup, this appears to be a mistake by Amazon and some of the pages went live before they were supposed to.
Right now Amazon has approximately 2.7 million books and about 120,000 audiobooks through Audible. The big problem for Amazon will be getting publishers to participate. Oyster has Simon & Schuester and HarperCollins, but I doubt either publisher will be quick to participate without some serious incentives from Amazon.
But given my review of Oyster, if this were available for kindle, I would subscribe.