I used a couple of different site monitoring tools over the years and Pingdom is a breed apart. I switched to them a few weeks ago after PokerDIY went down while I was sleeping and suffered 4 hours of downtime that was fixed by a App Restart. Now if that happens I get an SMS to my phone which will wake me up so I can do something about it.

There is a starter package which is free with 20 SMSs. It's definitely the most polished service I have seen (some use bits of text on your site whereas this one uses more sophistacted networking tools). I tried out a couple and Pingdom was the quickest to respond (I have it set to ping every minute and alert me if it's down for longer than 4 in a row (installing mods can cause it to not respond for a minute).

One look at their website separates them from some of the other services I have seen. If PokerDIY goes down a friend of mine in Mexico and in the UK also get an email (much to their annoyance ;) and have been instructed to get hold of me too... there's loads of little features like this.

It's a web 2.0 online service of a fairly old requirement - definitely worth checking out if you want to monitor your site! (I don't get anything from them for saying this, alas ;)

Entrepreneur

PokerDIY Tournament Manager - PokerDIY Tournament Manager<
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it really sounds interesting, I will have a look at it :)