Empathy - Apps/Empathy - GNOME Wiki!
GoToWebinar - Webinar & Online Conference | GoToWebinar
Pidgin - Pidgin is an easy to use and free chat client used by millions. Connect to AIM, MSN, Yahoo, and more chat networks all at once.
Zoom - Equip your team with tools designed to collaborate, connect, and engage with teammates and customers, no matter where you’re located, all in one platform.
Trillian - Trillian is a decentralized and federated instant messaging platform that lets your whole company send private and group messages, keep tabs on what co-workers are doing, share files, and much more.
WebEx - Cisco WebEx Web Conferencing, Online Meetings, Desktop Sharing, Video Conferencing