Pingdom - With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.
ClouDNS - ClouDNS is a platform that allows users to keep their websites, data, and network security all the time.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
EuroDynDNS - Dynamic DNS allows domain names to be assigned to a computer with a dynamic IP address.
Better Uptime - We call you when your website goes down
ChangeIP - The Fastest and Most Reliable Dynamic DNS