Slack
Slack is a proprietary business communication platform which offers many features, including persistent chat rooms (channels) organized by topic, private groups, and direct messaging. Slack integrates with many third-party services and supports community-built integrations, including Google Drive, Trello, Dropbox, Box, Heroku, IBM Bluemix, Crashlytics, GitHub, Runscope, Zendesk and Zapier.
By bringing people together to work as one unified team, Slack transforms the way organizations communicate.