There is a fine article by Danny Zacharias (contributor to the equally fine deinde.org blog on "discussion and resources for biblical scholars") on the Society of Biblical Literature site entitled, "The Wired Scholar: Five Free Tools You May Not Know About." He describes some of the neat resources available through Google and LibraryThing. I would particularly highlight (and I now have bookmarked) his references to the following sites: BIBLE, JUDAISM, CHRISTIANITY via Google Book Search (which contains a listing of links to Migne's Patrologia Graeca and Patrologia Latina) and the Free Books in Biblical Studies and Related Fields. As if I didn't already have too much to read...
Two items I would add to the list:
- Amazon's Search Inside feature: If you search on Amazon for keywords, it not only looks at titles, but it also look inside books. This only applies to some books which have the "Search Inside" feature indicating that the books have been scanned, but I have definitely benefited from using this technology to find sources I would otherwise have missed.
- Amazon's YourMediaLibrary: If you have an Amazon account, it already knows everything you have ever purchased. You can add tags and comments to anything, and you can also add any item whether you've purchased it or not using ISBN, UPC, or ASIN codes. It's similar to LibraryThing, although it isn't as helpful as an academic resource linking to other book lovers, but it doesn't appear to have any limits. Printing options are very limited, and it is not really a bibliographic tool, but it is a great organizer.