Skype - Stay in touch with your family and friends for free on Skype. Download Skype today to chat and call on desktop and mobile.
Tragofone - White-label VoIP Softphone with WebRTC and Auto-provisioning
Digsby - Tagged makes it easy to meet and socialize with new people through games, shared interests, friend suggestions, browsing profiles, and much more.
Lingo - Empower Creation and Ensure Brand Consistency. Build and Share libraries of visual assets with your entire team — all from your desktop.
Facebook Messenger - Facebook Messenger is a faster way to message.
tSIP - tomeko.net/software: SIP client for Windows.