LibraryBIN is an online site where you can buy e-books and audio books, but it is more than that. It supports libraries. If you work in a library in the US it would be a particularly benefitial site, because when a customer purchases a product some of the proceeds will go to a participating library of their choice.
For the rest of us, the site provides interesting statistics on the most downloaded e-books and audio books in a number of different countries, including Australia. The categories are for adult fiction, adult nonfiction, juvenile fiction, and juvenile nonfiction. Checking these statistics occasionally will help when choosing texts for the library, and provides librarians and english teachers with titles that may encourage students to increase their reading.