Silly but fun. I tried an unpublished novel that I have rewritten repeatedly for years now, and got Stephen King. Then I tried a more recent short story and got Lewis Carroll. I'll be damned if I can think of a lesson to draw from that progression.
It is kind of fun. I put two separate articles from the same non-fiction book I'm working on and got William Gibson (again) for one, and David Foster Wallace (again) for the other.
I tried it with a number of pieces from various works, and came out Stephen King, H.P. Lovecraft, James Joyce, Jack London, and like who-the-hell is David Foster Wallace? (Actually a deceased writer with one best seller according to wiki ... and we know how accurate wiki is.)
Apparently, Alexander Dumas writes like Ian Fleming ... and surprise of surprises, Arthur Conan Doyle writes like ... Arthur Conan Doyle. (The piece did have an inordinate number of the name "Holmes" it it though.
I plugged in three first pages and got David Foster Wallace (?!), Kurt Vonnegut, and Chuck Palahniuk. Who are these guys? I know I hate Kurt Vonnegut, and I've never read the others. Should I quit writing now? Or start reading some Palahniuk?
Maybe the site is run by the estate of David Foster Wallace. He's the only guy on here no one seems to have heard of, and he's cropping up everywhere...
I put some dedicated time into submitting stuff for an article I was writing for Examiner.com. I used consecutive sentences from the same published novel, and for the most part a different name came up for every sentence. You might want to read my results at http://exm.nr/writelike
It is an interesting gimmick, but I would say pretty innacurate.