Recently they added the ability to also buy the audiobook version and the app *syncs your place* so you can switch between the two formats. That's a pretty amazing idea.
But the app doesn't help the author. He said he had a Nook. Thanks to the recent firmware update people with a Nook Color or Nook HD can get then app, but if you have the eInk based "normal" Nook, you're just out of luck.
As DRM goes, Amazon has done an excellent job of reducing annoyance. They don't try that "you can only read this book on 2 devices, ever." stuff that we've seen elsewhere. But I get the feeling the only reason Amazon's DRM is so unobtrusive is they were so overwhelmingly powerful they could force publishers into a relatively consumer friendly system. We're lucky Amazon cares more about selling books than trying to wring money out of Kindle hardware sales, or the DRM would have been a lot worse.