Lock-in. That's what we call it when you're dependent on a specific vendor for particular services. When you buy a single-serving coffee machine boasting convenient, mess-free coffee inserts, like Keurig K-Cup or Nespresso, you're bound to its brand of coffee pods. When you purchase digital music on iTunes, proprietary formats and digital rights management (DRM) make it difficult to listen to it outside of Apple’s service.

Lock-in works because it produces switching costs, the financial or time burden that makes changing over to another vendor costly or inconvenient. Switching off K-Cups requires you to buy a new coffee machine. When you subscribe to a cable or Internet service, the misery of arranging and installing competing service creates lock-in as effectively as physical incompatibility might do for a packaged good.

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