join.me - Instant screen sharing. Instant Aha!
Twilio - Brings voice and messaging to your web and mobile applications.
WebEx - Cisco WebEx Web Conferencing, Online Meetings, Desktop Sharing, Video Conferencing
MirrorFly - World's Most Scalable Voice, Video & Chat SDK for Small, Medium & Enterprises
GoToMeeting - GoToMeeting is a web conferencing service offering a range of services which are available on Mac, PC, iOS and Android devices.
Plivo - Plivo simplifies your customer engagement.