Matt Cutts is on the record as saying that exact-match domain names get a rankings boost. You may not have known, but exact-match domain names get their own search volume. People use Google like the address bar, and type in things like Homes.com or Travel.com. The correlation between search volume and boosts for exact match domains may be a coincidence, or maybe not. I mention this to explain why you might see a ranking boost for an exact match domain name with little or no search volume of its own – it’s part of a larger group that do have that user satisfaction and search volume.