Pretty good article from SI. One excerpt:
In 2001, with several million dollars from Nike, Salazar launched the Oregon Project, a challenge to the African hegemony in distance running. The program brought to Beaverton a handful of promising U.S. runners and gave them every legal advantage extant, from space-age training aids to the amenities of the Nike campus, which include a fitness center, testing labs, a two-mile wood-chip trail and the soft grass field on which Salazar would eventually collapse. But four years later the Oregon Project had produced only one moderately successful runner, Dan Browne, a 2004 U.S. Olympian in the 10,000 meters and the marathon. The lesson, Salazar says, is that "you can't take mediocre runners and expect them to achieve world-class results."
Salazar has since reconstituted the group, but with a twist. He's trying to develop 5,000- and 10,000-meter runners, and if they happen to be well suited to the marathon, he'll urge them to build up to that distance -- but only gradually, at the proper juncture in their careers. Unless a male runner has near-27:30 speed at 10,000 meters, Salazar doesn't regard his potential as world-class and won't take him on.
Good thing guys like Brian Sell, Clint Verran have an option...