There are about thirty services/resources I use with some regularity because of the value they provide. One of those services is website monitoring provider InternetSupervision.com (a WM advertiser). There are hundreds of website monitoring services available, and I'll list a few others below that I've tried and that I think work well. But InternetSupervision stands out in my opinion because of the type of alerts they send and their embeddable uptime reports feature. There's a free version available if you want to test it out - no invites required.
Much like other website monitoring services, InternetSupervision monitors website availability from multiple locations around the world. The manner in which they provide notification, however, is impressive - email, SMS and voice. You read that correctly, voice. A customer support person - regardless of what time of day it is - calls you on the phone to, in my experience very politely, tell you that your website is unavailable.
If you're like me, you are not always sitting in front of your computer, and when you are, you're not always checking email. The same goes for SMS. I don't always have my mobile phone with me. But the landline phone is always around and should something happen to one of my websites (like a serious failure), then one of the Internet Supervision operators calls me - nice touch. I hate to admit it, but it's actually happened quite a few times. Users set up a call list, and the operators call until they reach someone. This happened to me once on vacation. I had my office number set up first (but I wasn't working), my home number second (but I wasn't there either) and my mobile number last. They actually called on all three numbers until they reached me and told me the site that was acting up, and then sent a text notification to tell me that it was finally active again. What a relief.
The next reason I use InternetSupervision is because of the embeddable uptime reports (shown below). I can give users (prospective advertisers) an idea of the availability of the site. They understand that the site, as websites will do, occasionally goes down, but still achieves the elusive five 9's (%99.999 uptime). Good choices on hosting clearly help, but you have to wonder how low it would be without a reliable website monitoring company.
A few other very well respected web monitoring solutions include InternetSeer.com, Mon.itor.us, AlertSite.com and host-tracker.com.
Here's a sample of an embeddable uptime report from InternetSupervision.com: