A site monitoring service is just what the name implies. In the event your site or server goes down, it notifies you via a variety of communication channels, including text message and email.

I’ve heard of instances where a webmaster didn’t realize a site was down until days later. By then, it is often very hard to regain lost traffic and revenue loss can be quite high. So do yourself a favor and use site monitoring. It’s cheap and saves a lot of hassle in the long run.