ClickMeeting - Collaborate with partners and clients using ClickMeeting professional web conferencing software. Try it now, FREE!
SocialEngine - Socialengine PHP: Elevating Your Online Community Experience.
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.
BuddyPress - WordPress social networking in a box.
WebEx - Cisco WebEx Web Conferencing, Online Meetings, Desktop Sharing, Video Conferencing
phpFox - phpFox is a powerful social network platform for niche communities