Teams Passes Slack: What a Surprise

Numbers Chart the Progress of Teams

The news that a Spiceworks survey found that 21% of organizations surveyed use Teams against 15% using Slack (both still behind Skype for Business) seemed to surprise many commentators. Clearly they haven’t been paying attention to the numbers published by Microsoft at Ignite 2018 (and analyzed here).

In September 2018, Microsoft reported that Teams is used by 329,000 organizations. Sixty of those organizations have more than 10,000 Teams users and in the largest (Accenture) Teams has over 100,000 users. Some quick math puts the total between these organizations at a minimum 6.1 million. Given that Office 365 grows at about 3 million new users per month (and has done so for several quarters), it’s reasonable to assume that a few more organizations have joined the 10K club and that the overall total is now climbing close to 350,000.

Maybe 33 Million Teams Users

In October, I estimated that Teams might have 33 million users. That’s a lot, and it’s much more than Slack can count (around 8 million in May 2018). The free version of Teams is swelling the numbers, but I think a lot of growth is in Office 365, fueled by Microsoft’s determination that Teams will replace Skype for Business Online as quickly as they can make the transition happen. Stopping new tenants with less than 500 seats from being able to choose Skype for Business Online is one example of how Microsoft is driving the change. Forcing other smaller tenants to move to Teams is another.

And More to Come

It’s reasonable to assume that Teams will have taken over from Skype for Business Online in the majority of Office 365 tenants by the end of 2019.  Much of the 44% of large businesses running Skype for Business today will run Teams then, so its lead over Slack will be even larger.

Indeed, the only reasons why anyone running an Office 365 tenant now have for continuing to pay good money to run Slack are a) inertia and b) the lack of good migration features to move Slack content to Teams. The migration issue should be solved when Microsoft delivers a Graph-based API to allow ISVs to read and write message and graphic content into the Teams Azure-based services at scale.

Inertia kills many transformations but I think that the integration between Teams and the other Office 365 workloads and Azure Active Directory (with all its benefits like features such as MFA and conditional access) makes it very easy for an organization to choose Teams over Slack.

Email and Chat

One of the interesting points in the survey was that: “Only 16 percent of IT professionals believe chat apps will replace email within three to five years, compared to 25 percent who said this in 2016.”

While again I am not surprised because I have been saying for years that Teams won’t take over from email, but it is interesting to see a relatively sharp reduction in the numbers of IT professionals now sharing the view. Chat applications can be better than email for certain conversations, and I have noted a reduction in the number of messages I receive and send daily (as reported in MyAnalytics), so I see how Teams has become a part of my daily communications – but email is still there and isn’t going away anytime soon.


For more information about Teams, read Chapter 13 of the Office 365 for IT Pros eBook.


One Reply to “Teams Passes Slack: What a Surprise”

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.