First off, everything is Quicklook-capable and can be viewed in CoverFlow, which is awesome. You can thumb through your books just with a few keystrokes. You can share your library via .Mac and Bonjour, which means while using Wi-Fi at Barnes and Noble, you can actually get book recommendations from anyone else on the network with you.
Finally, Scott reveals a strange but interesting new feature. Apparently, in its pre-release incarnation, you can also track tools. That's right-- the screenshot above is not Photoshopped (not by us, at least). Scott even suggests there might be other possessions to track, but we'll have to wait for the official release to see just what the Delicious team have cooked up.