Eighteen fictionaries are currently available across several genres including classic books, SF, and fantasy. The content is drawn from many of the same sources as the Kindle X-Ray: people. According to Tech Cocktail, the details in a fictionary comes from the multitude of community-driven wikis already available.
Fictionaries is the brainchild of Dave Byard. It's a project he's been working on for a couple years now, but he only got serious about it about 6 months ago when:
"I gave it to a couple of friends and they spurred me on to do something with it because they liked it so much," says Byard.
Due to the source of the content, Byard doesn't feel he can charge for a Fictionary, so they are all free to download. Currently he has ads on his site to defray the costs, and he is also in talks with indie authors who want to get featured on the site with their own Fictionaries.
This is a pretty cool idea, and if Amazon hadn't already come up with a better idea (X-Ray) then fictionaries could have been a big deal. Byard has even thought up a couple clever refinements, including offering spoiler-free fictionaries. For example, a fictionary for a Game of Thrones (the first book in the series) would hypothetically exclude details from later books in that series, thus saving you from learning that nearly all of the characters you like are killed.
But as cool as this is, there is a downside. You can only load a single dictionary, so if you choose to load a fictionary you'll have to do without a regular dictionary.
But in spite of that limitation, I hope more fictionaries are created. I am following several series which have grown into "cast of thousands" situation and could really use a fictionary to keep the characters and locations straight.
Byard uploads new fictionaries as he reads new books or upon request, so I just might go ask.