Four owner managed hosting companies will take considerable pride that Yahoo, with its colossal financial resources and economies of scale, did not come top, with INetU edging out Datapipe, IPowerWeb, and Pair Networks by virtue of an extremely reliable Q4, and faultless December.
It's nice to be working for one of the best. Netcraft keeps a running log of the top ~50 hosting providers. We're always right up there: http://uptime.netcraft.com/perf/reports/Hosters.
I read their FAQ on how they collect the data. Basically they're just hitting www.pair.com and keeping track of how fast a connection is made, a byte is sent, and the request is complete. Also the number of failures, if there were any. In the year-end report we had 0.08% of the requests fail. These requests happen at 15 minute intervals.
We overhauled our website last year, with a brand new design and backend. So the robots probably tried to hit us when we were rebuilding the website. There may have been other things happening through the year, such as apache or kernel upgrades. If we would have timed those upgrades just right, Netcraft wouldn't have missed us. Alternately, we could have rerouted traffic to another computer that explains "bbiab" or something.
What is my point? I'm not sure. From a marketing perspective the ranking is nice to see. From a technical perspective I've now considered all the ways it's possible to fool Netcraft into seeing our host up when we have regular maintenance slotted.