ZeroMQ

Why Use the GPLv3 for Public Specifications?

The license you choose is particularly crucial for public specifications. Traditionally, protocols are published under custom licenses, where the authors own the text and derived works are forbidden. This sounds great (after all, who wants to see a protocol forked?), but it is in fact highly risky. A protocol committee is vulnerable to capture, and if the protocol is important and valuable, the incentive for capture grows.

Once captured, like some wild animals, an important protocol will often die. The real problem is that there’s no way to free a captive protocol published under a conventional license. The word “free” isn’t just an adjective to describe speech or air, it’s also a verb, and the right to fork a work against the wishes of the owner is essential to avoiding capture.

Let me explain this in shorter words. Imagine that iMatix writes a protocol today, that’s really amazing and popular. We publish the spec, and many people implement it. Those implementations are fast and awesome, and free as in beer. They start to threaten an existing business, whose expensive commercial product is slower and can’t compete. So one day some representatives of that business come to our iMatix office in Maetang-Dong, South Korea, and offer to buy our firm. Because we’re spending vast amounts on sushi and beer, we accept gratefully. With evil laughter, the new owners of the protocol stop improving the public version, close the specification, and add ...