If I'm understanding your comment right, you could use Calibre to do this just as easily, possibly with more information. There's no requirement to actually hav

If I'm understanding your comment right, you could use Calibre to do this just as easily, possibly with more information. There's no requirement to actually have a file associated with a record in Calibre, so you can add your comments into the metadata (or have the record point to a file with comments and notes instead of/alongside the ebook). I use a Calibre database to keep track of my bookshelves; the metadata includes ISBN, my review, my rating, average online rating from various sites, where I got the book, similar and associated books, etc. It should be relatively simple to get a single-click plugin going that brings up a search for the ($ISBN|$ASIN|$TITLE+$AUTHOR) of the currently selected record. The only thing missing here is public access (the buying gifts part)