From a newsgroup post dated May 28, 2013:
There’s a website at http://iwl.me/ called “I Write Like” that purports to analyze one’s prose and match it to a well-known author. I tried it out last night.
Taking a passage from On A Field Sable told me I write like Jane Austen. A chunk of One Hundred Suns, though, matched Arthur C. Clarke.
Graveyard Girl was where it really got interesting, though — my first pass got Cory Doctorow. I decided the sample I’d used wasn’t typical, so I tried again and got Jack London. Then I removed one paragraph from that, and it was Cory Doctorow again.
Not exactly consistent results.
http://iwl.me/ is still there.