Most hosting companies were unaffected by a number of events affecting Web reliability during May. A number of highly-trafficked Internet sites experienced downtime May 24 as Akamai experienced network problems, while the first week of the month saw some networks congested by the Sasser worm. Meanwhile, denial of service attacks hobbled a number of e-commerce and security sites.
Netcraft measures and makes available the response times of fifty 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.