Pingdom, a website tracking service has issued a study of the downtime experienced by the top 20 websites according to Alexa. The nutshell of their finding is that amongst the top 20 websites the only 2 sites to have a downtime of more than 4 hours in 2007 to-date are properties of Google, Youtube and Blogger.
Yahoo remained the most reliable of the lot with zero downtime, is this one reason for it being on top? Google search came as no 2 with a downtime of 7 minutes. The next worst performer after Google was Microsoft with msn and live.com having downtimes of almost 3 hours and 2 hours respectively.
Pingdom is a service that tracks websites. Some of the features it provide include notification of your site health via sms and email, uptime and response time reports, multiple global check locations to measure performance around the world and other such features. Plus you don’t need to install anything, so you could just start using it right away.