Adding books is now possible for normal humans....

The previous "enter the magic ISBN" form has been replaced with something a bit more human-friendly. Now you can enter keywords (which might include author, title, ISBNs, or other actual keywords) and as you type, a search against Amazon will be performed, with potential results shown in a drop-down list, with cover art if available. Select one, hit "Add this Book", and presto, your book is added. You can try it out here. As before, you can also enter an ISBN/Title/Author combination if the book you are after isn't in Amazon's catalog.