WebGazer is an uptime monitoring platform that checks if your website is up as it should be and notifies you if anything goes wrong
UptimeRobot - Free Website Uptime Monitoring
Optimizely - A/B testing you'll actually use.
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.
VWO - Use VWO to tweak, optimize & personalize your website with minimal IT help.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Evolv - Evolv is the visual editor for web-based projects that are used to find better ways to connect with customers in order to improve marketing economics.