The full version of Workplace will be free until September 30th, but Facebook plans to charge a modest monthly rate of $3 per person for the first 1,000 people, $2 per person for the next 9,000 users, and $1 per person after that. Slack does offer 5GB of storage and service integrations with its free service, but you're looking at a minimum of $6.50 per month for perks like additional storage or searching chat archives. That can add up quickly if you're part of a large outfit.

Workplace is also getting bots that can automate tasks in group chats, such as ordering food for a long meeting or Lyft rides for the trip to an event. You'll also have the option of broadcasting live video from pro equipment, such as a high-end camera at a presentation.

Should Slack be worried? That's hard to say at this stage. Facebook's name and resources will certainly get its foot in the door, but Slack has years of lead time and a presence on virtually every major platform. Also, some organizations may prefer Slack precisely because it isn't Facebook. You don't have to think about sharing your Facebook identity with your office, for example. It won't be surprising if Workplace makes further inroads with its free tier, but it isn't guaranteed to dominate.

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