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.
Postscript - Like Mailchimp for SMS
ClickMeeting - Collaborate with partners and clients using ClickMeeting professional web conferencing software. Try it now, FREE!
Tatango - Tatango is a mobile messaging platform for agencies.
WebEx - Cisco WebEx Web Conferencing, Online Meetings, Desktop Sharing, Video Conferencing
Flowroute - Flowroute provides direct access to telephony resources - such as calling, messaging (SMS & MMS), call routing, SIP Trunking and Communication APIs.