Sounds like the title if a YA thriller, with eBay fighting evil pirates ripping off the legitimate sales of authors (like Jim Butcher and Richelle Mead). Not the case, though. eBay pays no attention to copyright infringement unless somebody goes to the trouble of verifying it and reporting it to them, and THEN they won't end a listing unless and until they can actually get in touch with the rights holder and verify that what's being sold is an unauthorized copy. Meanwhile, sales go on as usual, and eBay, their PayPal subsidiary, and the pirates all rake in the profits on the sales. When a publisher's lawyers get in touch with eBay, they will end the listing and revoke the seller's ID, so the seller picks another ID and goes back into business as usual, and the cycle starts all over again.
It used to be a lot of work to be a Book Pirate, they'd actually have to buy a copy, or at least check it out from the library, and physically scan the pages. Now, with the rise of ebooks and audio books, lots and lots of people have figured it's an easy, no-risk way to steal, using eBay to fence the goods. Somebody gets one copy of a legitimate ebook, uses software to convert it to a PDF file, and can then crank out an infinite number of copies. From what I can see from looking around eBay, some of the sellers may have bought some other pirate's CD originally, and now they're cranking out pirated copies of some other pirate's pirated booty. I saw a couple of amusing instances of Negative Feedback, where one pirate complained another seller was pirating him, and then leaving negative feedback about the first pirate to drive buyers to the new pirate's CD. There is no honor among thieves.