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Why Microsoft's Ban of Rival Slack May Be a Mistake—Data Sheet

Aaron Pressman

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Happy Monday. Aaron here, back from vacation, essay writing and curating this week, as Adam goes off on a break.

Catching up on all the tech news while I was away, I was sent spiraling down memory lane by Friday’s GeekWire scoop that Microsoft maintains a list of “prohibited and discouraged technology.” Said list is said to ban popular work messaging app Slack (which we use at Fortune) and online grammar checker Grammarly, while discouraging use of Google Docs, Amazon Web Services, and cloud security company PagerDuty. The various rationales offered in the document cite security concerns, but also the obvious rivalry aspects. For example: “Slack Enterprise Grid version complies with Microsoft security requirements; however, we encourage use of Microsoft Teams rather than a competitive software.” Microsoft declined to comment to GeekWire.

There’s a long history of tech companies eschewing the products of their competitors. Google stopped its employees from using Microsoft Windows a decade ago, also citing security issues, and Microsoft discouraged use of the Apple iPhone early in the smartphone era.

Personally, I was sent back to my tenure at Yahoo, when CEO Marissa Mayer only allowed use of the company’s ad-laden, performance-challenged web client for all work email. The proffered explanation was that the limitation would prompt employees to offer feedback–and likely push for rapid improvements–to help the engineers on the web email team better the product. That happened some, but it also sapped the productivity of people in jobs that depended on robust email communications capabilities, like, say, salespeople–or reporters.

The new banned list at Microsoft is a bit surprising given that part of CEO Satya Nadella’s successful strategy for reviving the software giant has been to embrace other platforms and abandon the only-made-here mindset. At the very least, deeply knowing the competition would help ensure Microsoft’s own products keep pace. Historically, that may have been part of the problem behind what Bill Gates just called “one of the greatest mistakes of all time.” Appearing at an event at VC firm Village Global last week, Gates admitted he made that all-time whopper by failing to create the mobile operating system alternative to Apple’s iOS. Instead, Google, where co-founder Sergey Brin was an early fan and avid user of the iPhone, grabbed the other spot. Gates called it a $400 billion mistake.

Hopefully, history won’t repeat, despite the bans.

Aaron Pressman @ampressman aaron.pressman@fortune.com