It is a cross-platform mobile messaging app for iPhone, BlackBerry, Android, Windows Phone and Nokia. It allows users to send text messages and voice messages, make voice and video calls, and share images, documents, user locations, and other media.
Imagine all your team communication in one place, instantly searchable, available wherever you go. That’s Slack. All your messages. All your files. And everything from Twitter, Dropbox, Google Docs, Asana, Trello, GitHub and dozens of other services. All together.
See content and chat history anytime, including team chats with Skype that are visible to the whole team. Private group chats are available for smaller group conversations.
HipChat is a hosted private chat service for your company or team. Invite colleagues to share ideas and files in persistent group chat rooms. Get your team off AIM, Google Talk, and Skype — HipChat was built for business.
Mattermost is modern communication from behind your firewall.