Have you ever tried to load your site or blog only to find it was down? Then you contact your service provider only for them to tell you that your site is up everything is running as normally. Your service provider tells you that the problem is with your connection or computer. Now you need a way to confirm what they are saying. There are a number of free services that can check your site for you.
Go to either or all of these checking sites and enter your sites or blogs URL and submit it. The checking site will confirm wether or not your site is running or not and report to you.