{"id":22465,"date":"2026-02-26T09:00:00","date_gmt":"2026-02-26T17:00:00","guid":{"rendered":"https:\/\/www.microsoft.com\/insidetrack\/blog\/?p=22465"},"modified":"2026-03-05T09:10:07","modified_gmt":"2026-03-05T17:10:07","slug":"protecting-anonymity-at-scale-how-we-built-cloud-first-hidden-membership-groups-at-microsoft","status":"publish","type":"post","link":"https:\/\/www.microsoft.com\/insidetrack\/blog\/protecting-anonymity-at-scale-how-we-built-cloud-first-hidden-membership-groups-at-microsoft\/","title":{"rendered":"Protecting anonymity at scale: How we built cloud-first hidden membership groups at Microsoft"},"content":{"rendered":"\n

Some Microsoft employee groups can\u2019t afford to be visible.<\/p>\n\n\n\n

For years, we supported email\u2011based communities internally here at Microsoft whose very existence depends on anonymity. These include employee resource groups, confidential project teams, and other sensitive audiences where simply revealing who belongs can create real\u2011world risk.<\/p>\n\n\n\n

Traditional distribution groups make membership discoverable by default. Owners can see members. Admins can see members. In some cases, other users can infer membership through directory queries or tooling.<\/p>\n\n\n\n

That model doesn\u2019t work when anonymity is a requirement.<\/p>\n\n\n\n

\"A<\/figure>\n\n\n\n
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\u201cWhen the SFI wave hit, it was made clear to us that we needed to keep our people safe, and to do that, we needed to build a new hidden memberships group MVP. We needed to raise the bar with modern groups, and we needed to do it in six months or miss meeting our goals.\u201d<\/p>\nBrett Reifers, senior product manager, Microsoft Digital<\/cite><\/blockquote>\n\n\n\n

For over 15 years, we relied on a custom, on\u2011premises solution that enabled employees to send and receive messages through groups with fully hidden memberships.<\/p>\n\n\n\n