There is some speculation that this might go beyond just ebooks. It is only speculation since eBay hasn't yet given complete details of what is included.
However there is some thought it might cover everything delivered through Internet downloads or by e-mail. If true, in addition to ebooks it would include graphics and digital photos, software, domain names, Web site templates, Web hosting and numerous other types of goods which are sold on eBay in digital format.
Here is a 2 page article that provides a lot of interesting information about this. It also has some examples and thoughts from some eBay sellers. The pages aren't long. You might need to scoll down a little to read the article
eBay Boots Digital Goods Off Auction Block