LibraryThing. I know there are other websites to catalog the books you read or own or have ever looked at (judging some), but Library Thing really understands people who love books. One of my favorite features is the libraries of famous folks. People like Thomas Jefferson, John Adams, Ernest Hemingway, Marilyn Monroe, and Tupac have had their personal libraries catalogued for the curious.
These Legacy Libraries, as they're known, are group cataloging projects usually undertaken by many members. The Legacy Library project has been going for a couple years (or so), and the contents are amazing! You can explore the discussions and see what libraries are included so far here: http://www.librarything.com/groups/iseedeadpeoplesbooks.
And, if you have recorded your own library (like I have), you can compare books. The first 200 books are free, after that you have to buy a membership, which has a $25 for life level which I bought a long time ago, and it has paid for itself many, many times over.
If there's one thing Library Thing loves, it's statistics. For instance, I now know I share 55 books with Ernest Hemingway, but only 5 with Sir Walter Scott.
Another person, rather, character, I share 5 books with is Roger Mifflin. Haven't heard of him? Maybe it's been a while, but Mr. Mifflin is the owner/ operator of Parnassus on Wheels and The Haunted Bookshop, both books by Christopher Morley.
I read both books while enjoying the Great Xmas Eve Blizzard of '09 (record snowfall in Oklahoma!), and noted the books mentioned that belonged to Mifflin, or references the character made that could be traced to a specific book. Then I created a catalog of Roger's personal library and voila, we now have our first ficitonal library among the Legacy Libraries. You can compare your books with Roger's here: http://www.librarything.com/profile/RogerMifflinLibrary.
Also, in the vein of Christopher Morley, whom I truly adore-
Happy Birthday Sherlock Holmes! Today, January 6th, is widely recognized to be the master detective's date of birth. Morley, of course, was a huge fan of Sherlock Holmes and was the founder of the Baker Street Irregulars, one of the more famous bibliophile societies in the USA.
If you've seen the new Sherlock Holmes movie, get out and find one of the books. I did. I found a small stack at my local used bookstore for under a few bucks. All of them are quick, fun reads. I'll celebrate Sherlock's birthday by continuing to read The Valley of Fear, which I've never read before and am enjoying.
What about you, gentle reader? Do you have a favorite Sherlock Holmes read? If you do, maybe you should also check out the podcast I Hear of Sherlock Everywhere: http://www.ihearofsherlock.com/, a podcast (and a blog too) related to all things Sherlockian.