Life in the Fast lane here... The article,
"The Search for the Fastest Engine" [fastcompany.com], includes some quotes from John M Lervik, the CEO of Fast. Basically a PR article, it doesn't tell us what the algo is, but there's some material of interest.
No relationship that I can tell between Fast and FastCompany, but the article suggests that a "third generation" search engine like Fast could distinguish between Fast and Fast. ;)