Interesting service: Is it down right now?

Sitemeter is a useful service for tracking visits to my blog.  I typically check Sitemeter's page for Why Homeschool a couple times a day. 

Recently Sitemeter was down for a day or two.  I did a Google search to see if there were any details about why it was down or when it would be back up.  I came across Is It  Down Right Now?  It tracks various web sites and reports on if htey are down and if so how long the site has been down.