Let’s say you are reading your favorite RSS feed or visiting your favorite news aggregator (digg, slashdot, whatever…). You click on a link that is referenced on the site and …blam…404 file not found. For whatever reason, the site is currently down or experiencing database problems, DNS issues, they didn’t pay their electric bill…whatever.
That is where Mr. Uptime steps in. It notices that you couldn’t reach the site and offers to monitor the page in question until it becomes available. As soon as it’s available, it will offer to open that page in a new tab, window or simply alert you that it’s available now. I have mine set to alert me and open a new tab in the background, so it doesn’t disturb whatever I’m reading at the moment.
There is also a nifty menu option that allows you to highlight some text on a page (such as an SQL error) and set a rule to watch for that SQL error to go away. It then notifies you when that SQL error goes away (see image below).
That about covers it. You can download the Mr. Uptime FireFox add-on here. It’s free and pretty cool.
No go forth and surf; and don’t worry about site getting Dugg or Slash Dotted. Mr. Uptime can keep an eye on them for you.