A little over a year ago, Microsoft Teams reached 180 million users and when asked about the milestone, Slack CEO Stewart Butterfield claimed that the platform was not a threat to the competiting platform.
Fast forward 365 days and Butterfield is using Twitter to defend a new antitrust suit Slack is bringing up against Microsoft in the EU, claiming the company is crushing the competition.
Some notes about https://t.co/ii0SDULm7v, since it got a lot of đ.
Over 3+ years since Teams was announced, weâve grown >500% (our enterprise business grew >1,100%). We continue to win with the biggest companies in the world. We’ve lost 0% of our 100 largest customers ⊠đ§”/n
â Stewart Butterfield (@stewart) July 22, 2020
In a lengthy and sometimes convoluted tweetstorm, Butterfield attempts to clarify Slackâs new antitrust lawsuit against Microsoft and what he believes is its snowballing enterprise presence.
According to the public statements about the suit, Slack believes that Microsoftâs ability to tie its enterprise chat feature to its dominant productivity suite constitutes anti-competitive behavior from the company.
The crux of Butterfieldâs online tirade appears to be that people already using Microsoftâs Office productivity suite arenât given an opportunity to try Slack and subsequently choose it over Teams. Butterfield, along with other Slack executives would like the EU to force Microsoft to remove Slack from Office and make it a stand-alone product while charging a âfair priceâ for it.
While Slackâs argument may seem to echo that of Microsoftâs previous 2000s antitrust suit, it seems the company may be leaning more on nostalgia than an actual case.
âMicrosoft is reverting to past behavior.â
Slack is seeking to hold Microsoft âaccountableâ in the EU where the bar for anti-competitive behavior resides in the general competition ether and is arguably a lower bar to hurdle than in the US where anti-competitive behavior is defined at the consumer level.
The potential issue going forward for Slack is that during the anti-trust probe of the 1990s for Microsft, the company wasnât found guilty of âbundlingâ but of other illegal tactics that arenât as apparent with its enterprise chat competition.

Furthermore, Butterfield and Slack are aiming their crosshairs at Microsoft but may be holding a blindspot for a more immediate threat in Googleâs latest bundling effort that would pose a greater risk to Slackâs longevity.
Slack and Google Docs usage makes up a not too insignificant portion of the companyâs user base and if Google does figure out chat for its G Suite users, Butterfield may be back to Twitter with another antitrust justification tweetstorm soon.