iTunes App Store, namely via the Book category. As of this writing, 42 of the top 50 books by revenue are from the seller Thuat Nguyen, whose company website ("mycompany") leads to parked site www.home.com. A vast majority of these book apps were released in April, have little to no customer ratings or reviews, appear to be in Vietnamese (despite claims in the side bar that the supported languages are English and Japanese), and may or may not be infringing on copyrighted work -- we're noticing a lot of Dragon Ball art here. To give sales a sense of scope, Twilight series conclusion Breaking Dawn is hovering only at 34 right now.
So, how did these books hit the top of the charts? The other half of this story has to do with a claimed rise in iTunes account hacking, with a number of people reporting up to hundreds of dollars being spent unwillingly from their account to these specific books. Coincidence? Let's not mince words here, something is definitely amiss, and it's not looking good. Just to be safe, might wanna check your purchase history under Apple Account information. We've reached out to Apple and will let you know as soon as we hear back.
Update: We've yet to hear from Apple proper, but we do have an update of sorts -- 9 to 5 Mac reports all the "mycompany" titles have completely vanished from the App Store. We're not sure whether Apple decided to shut down the operation or the seller pulled them himself, so continue to keep an eye on your digital pocketbook until we know for sure.
[Thanks to everyone who sent this in]