In another sign of how heated the collaboration software market is getting, Microsoft has launched a free version of Teams, offering access to the group messaging and collaboration app without requiring an Office 365 subscription.Teams was launched as a rival to popular team chat platform Slack & which already offers a free version & at the start of last year; Microsoft bundled it with other Office 365 apps such as Yammer, One Drive and other Office tools.[ Further reading: Chat happens: Your guide to 11 group-chat services ]As of March, some 200,000 organizations were using the chat app & up from 125,000 in September & though Microsoft doesn&t break out monthly active user figures.