Today Slack is launching a tool that allows people from different companies to collaborate. (Slack Images)

Slack has had a clear message for Microsoft ever since the Redmond tech giant unveiled Teams back in November: Game on.

The day before Microsoft rolled out its workplace chat tool, Slack took out a full page ad in The New York Times with some “friendly advice” for its new rival. That competitive spirit is alive and well 10 months later. Slack is revealing growth numbers and rolling out a new feature, called Shared Channels, one day after Microsoft made a similar announcement. Slack shared the news at its Frontiers conference in San Francisco Tuesday.

Shared Channels creates a place for employees of different organizations (with separate Slack groups) to work together. Shared Channels allow users to chat, upload files, and use the other features of a standard Slack channel. Slack is also launching in French, German and Spanish today and will offer Japanese soon.

In today’s announcement, Slack revealed that it has grown to 9 million weekly active users in more than 100 countries around the world. The company says it has 50,000 paid teams, two million paid users, and $200 million in annual recurring revenue.

Yesterday, Microsoft announced its Teams program is now being used by 125,000 organizations, up from 50,000 at its official launch in March. Microsoft disclosed the growth numbers as part of a broader announcement of a new Guest Access feature on Teams, giving organizations a way to bring in freelancers or consultants on a project without revealing all of the Slack group’s business communications.

Guest Access is Microsoft’s answer to Slack’s Guest Accounts, which also allow freelancers and outside collaborators to join Slack teams temporarily.

Microsoft and Slack are fierce rivals but they’re hardly the only tech companies competing in the crowded enterprise collaboration space. Amazon, Google, Facebook, and other companies are all vying to carve out a share of the market, though some experts expect Microsoft to emerge as the frontrunner in coming years.

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