Visualping - Visualping is the easiest to use website checker, webpage change monitoring, website change detector and website change alert software of the web. Read more about Visualping.
Intruder - Intruder is a security monitoring platform for internet-facing systems.
Wachete - Track web page changes and get notified. Free Sign-up. Have all data in one place
Acunetix - Audit your website security and web applications for SQL injection, Cross site scripting and other...
Update Scanner - Update Scanner is a Firefox extension to monitor web pages for updates.
Horangi - Horangi is a leading cyber-security solution that provides instant response and threat detection for companies who lack the time and expertise to monitor their system.