Okay, I'm sold on Audiobooks. I'm not generally a huge fan of audiobooks (except for books read by David Sedaris or Sarah Vowell) but many times we have patrons (especially students, or parents of students) need/want audio versions of classic novels. It's easy enough to track down ebook copies of titles in the public domain - thank you, Project Gutenberg - but audiobooks aren't as readily available.
True, you have to stream the audiobook if you want free versions, so it's not great if you're going to spend a week in the Guatamelan jungle. But otherwise, with the wide availability of wifi (easy to locate thanks to Thing 3), it's a fairly useful app.
Wattpad was also on the agenda, and it's fine. But not nearly as Earth-shattering as Audiobooks.