From the press release:
The creator of the UNLODER™ that lets consumers sell ebooks and other media online, get store credit, and refresh a stale media library at a fraction of the price, is promoting its digital media resale tool as a means to winning a battle within the “war” surrounding the issue of illegal downloading. Lexink® announces its digital media resale solution as the ebooks market sits on the brink of an upcoming expected surge, catalyzed by the release of the iPad and iBooks.
This is probably never going to happen. I've tried to look at this from the viewpoint of an ebook retailer, and I don't see what they would gain. A new retailer would like this, yes, but in order to get a credit for a title you will have to have the cooperation of the original seller. (You can't sell a file if you still have access, and if you bought the file through Fictionwise then Fictionwise will need to remove the file form your account.) I think an established seller would see used ebooks as cutting into their current profits.
If this succeeds, it's going to be an uphill battle.