Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Skype for Slack - Move your slack discussions to a group skype call
Intercom Facebook integration - Read, manage & respond to Facebook messages from Intercom
Aircall Now - Make voice calls inside Intercom Messenger 📞💬
Crypton.sh - SMS - Secure Anonymous SMS in the cloud (and a phone number)
HandsFree 2 - Call and SMS in Mac using your Android phone via Bluetooth