In the latest newsletter, Susanne/Per of Pandia suggests that the SE world is perhaps developing into a two horse race.
I thought the following piece was intersting and seemed to support their line of reasoning
It's Fresher at FAST by Gary Price
On Monday, FAST announced that its alltheweb.com search engine, with an index of more than 625 million web pages, is completely refreshed every nine to twelve days. The search engine also catalogs more than 70 million integrated multimedia files.