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.
FlashStart - The FlashStart Cloud is a web filter for malware protections and to manage unwanted and offensive internet content.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
OpenDNS Umbrella - Cloud Security
Better Uptime - We call you when your website goes down
SPS Threat Avert - Is your network protected from DNS Tunneling and DDoS attacks, including PRSD and amplification?