GoTo Connect - Jive PBX is a communication solution that offers remote communication services to companies such as video conferencing, text, and chat services.
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.
BVoIP - BVoIP allows to easily add Cloud & On-Premise VoIP PBX to the product offering without having to re-invent the wheel or add another layer to the daily operations..
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Dialpad - Switch is a cloud-based phone system built for Google Apps users.
Better Uptime - We call you when your website goes down