Missive - Team communication app now supporting FB, Twitter & SMS
Slack - A messaging app for teams who see through the Earth!
Slack for Mobile - Rebuilt from the ground up
chatmego - Sign in to chatmego or create an account - start connecting new friends with me, share photos, videos, messages, a story, and vote with me
Sidechat by Mixmax - Chat & collaborate on emails, without leaving your inbox.
Loop Email - Emailing for teams: Organize your Inbox into channels 💌