Question2Answer - A Q&A site helps an online community to share knowledge.
RingCentral - RingCentral is the leading provider of cloud-based communications and collaboration solutions for small business and enterprise companies
Stack Overflow - Community-based Q&A part of the Stack Exchange platform.
Dialpad - Switch is a cloud-based phone system built for Google Apps users.
Stack Exchange - Stack Exchange is a fast-growing network of 84 [and counting] question and answer sites on diverse...
Aircall - Aircall is a call center software of a new generation designed for fast growing companies. Setup instantly and integrates to your CRMs