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.
Anturis - Anturis offers hosted server monitoring software (SaaS) for both Windows and Linux.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
LepideAuditor for Active Directory - LepideAuditor for Active Directory is said to be the must-have part of the IT environment and IT administration purpose.
Better Uptime - We call you when your website goes down
Crowd Vox - Crowd Vox is a secured, robust, fully configurable, and customizable review script that helps you to create feature-rich business directories.