BookLamp.org is currently in beta version. It describes itself as a Pandora for books. The matching process involves you selecting a book from their list of titles and then through an analysis of writing style, patterns, elements of writing, perspective, tone, and tense, they give you a recommended title list.
In order to play around, you have to register on the site, but it is free and painless. Then you can try it out.
Now remember, beta version! It has a very limited list of titles, mostly science fiction. And as it loads the title’s recommended matches onto the screen it seems to be redoing the matching process. This doesn’t make much sense to me, because the factors for these books have to already have been entered. Why not just give us the matches immediately?
And also let me unleash my librarian on them and say that simply looking at text and matching according to tense, tone and perspective are not enough. One needs to really match according to less tangible factors as any librarian can tell you.
Pandora has a very intricate matching system that works sometimes and fails amazingly others. I suspect this will be true here as well. I respect them for wanting to do this scientifically, but reading and books are so personal (as is music) that it is going to take some additional finessing to get it to really be an amazing engine for readers.
Something to keep an eye on, but not something to use with the public yet.