Office 365

Office 365 is Microsoft's transformation of licensed productivity software into a cloud-subscription service, a shift that converted a one-time purchase into a perpetual revenue stream while simultaneously making the user's documents, communications, and collaborative workflows dependent on Microsoft's cloud infrastructure. The technical architecture is unremarkable — web-based document editors, email hosting, video conferencing — but the business architecture is brilliant: by making real-time collaboration require a Microsoft account, a Microsoft server, and a Microsoft subscription, Office 365 transformed the office suite from a tool into a social graph that users cannot leave without severing their professional relationships.

The model has been widely imitated but rarely replicated. Google's Workspace competes on price; Microsoft's dominance rests on the accumulated file-format legacy of three decades and the organizational stickiness of enterprise procurement. Office 365 is not a product. It is a subscription to a network that your employer chose for you.

Office 365 proves that the most durable platform lock-in is not technical but social: when your job requires you to use a tool, the tool ceases to compete on quality and begins to compete on organizational inertia.