The new ebook service is a pleasant surprise. It was conceived as an alternative to building a coffee tablet style book into an app. Given the high cost of producing an app, I'm sure you can see the value of this alternative.
It builds on Blurb's existing tools, BookSmart and Bookify. If a photographer has already created a finished book with one of the tools, then making and releasing the ebook is simple. The resulting ebooks can then be sold via Blurb's bookstore and the publisher has full control over the price.
Now, my interest in this (besides the fact it's ebooks) is the $2 charge. At first glance that appeared to be a flat fee, but it's actually $2 per copy sold (and of course $2 for the first copy). Okay it's an automated conversion service, but it's also far less than other service I know of. And here I was, thinking to myself that ebooks have a high production cost. They must, because if they don't then that kicks one of the legs out from under Agency pricing.
It's not clear yet whether the ebooks have DRM, but given that they're sold by Blurb and open in iBooks I would bet that they are the relatively new fixed layout style ebook that Apple rolled out a few months back.