This is one of the small ideas we selected to add to WebmastersLookup. Webhosters and ISP's sometimes claim a 100% uptime of their service, but can they really proof it?
We have a job running every hour that checks the availability of a website (7 X 24). All checks are counted and stored in our database. Yes, we can tell if a website has a 100% uptime over a period of time. This means we can offer an independent availability proof. You understand why websites gladly link to this page. Members can add websites to the Availability checker and add a number of days of checking these sites.
All websites that enter this service get extra attention via a highly indexed web page providing 3 hyperlinks to these sites. The frequently running job generates a lot of traffic, that's why this cannot be a free service; it costs $ 0,50 a day per site.