Sites running on BSD operating systems occupied six out of the first seven places: Secure Dog Hosting runs OpenBSD, while New York Internet, INetU, USWest, IPowerweb, and Yahoo all use FreeBSD.
Netcraft measure and makes available the response times of fifty three leading hosting providers' sites The performance measurements are made at fifteen minute intervals from four separate points around the internet, and averages are calculated over the immediately preceding 24 hour period.
Fuller information on the measurement process and current measurements are available.