Yesterday, Microsoft announced it was pledging 60,000 patents under the Open Invention Network (OIN) license. While the move was historic, it was not surprising. Instead, it marks a logical culmination of a path the software giant tentatively embarked on as much as a decade ago. That evolution gained significant momentum accelerated with the departure of Steve Ballmer, and accelerated yet again as the success of the Linux distributed development model was replicated across more on more projects, covering technologies as varied as cloud computing, virtualization, and blockchains. 

On the surface, the significance of Microsoft's joining OIN lies with its agreeing to the terms of the OIN license. But in joining OIN, Microsoft may in fact be acknowledging the power of a far older social force: the community taboo.

Yesterday’s announcement is just the latest in a years-long series of Microsoft actions recognizing the realities of today’s IT environment. There’s simply no denying the fundamental role now of open source and, as importantly, the vital importance of being seen as a leader in OSS development.

That takes us back to the power of the taboo. For years now it has been clear that the marketplace will harshly punish anyone that tries to tax, or attack, the work of an important open source project. True, Microsoft reportedly earns some $3.4 billion dollars a year in Android licensing fees, and this has not kept it from participating in open source projects. By signing the OIN license agreement, it would appear that it will be giving up the right to charge these fees. But there’s more to Android than the Linux kernel, and those parts aren’t the work of a vibrant open source community.

Why is this taboo so important? Absent it, open source would be seriously vulnerable to patent suits. There’s a common misconception that those that contribute to open source have a legal obligation with respect to the whole code base, but this is not in fact true. Unlike standards, where everyone that contributes to a standard must either grant patent licenses on reasonable and non-discriminatory terms with respect to the entire specification, or disclose the claims that will be unavailable so that they can be designed around, a contributor to an open source code base makes commitments only as to the specific lines of code they contribute. And the legal validity of those commitments degrades as that code changes.

The point is that the hundreds of IT companies with large patent portfolios that have always declined to assert their patents against code bases have stood aside not because of a legal obligation, but because a taboo – if a company did assert a patent, it would become a pariah. Its code contributions would be rejected by open source communities and the best developers wouldn’t want to work for it.

In fact, the purpose behind forming OIN initially had more to do with allaying user fears of being sued by Microsoft than it did with providing real protection. It would be years before the OIN patent pool and those entitled to benefit from the OIN cross-license grew to a point where OIN’s impact could be significant. 

The formation of OIN was an outgrowth of an already existing history of individual companies making individual, public “non-assertion covenants” against users of Linux, software implementing the Open Document Format, and other emerging open source programs. Beginning in 2003, such pledges were announced by IBM, Motorola, Nokia, Oracle, Sun and others. In each case, the announcements were more for public reassurance than for real legal reasons – the companies weren’t going to assert those patents anyway. OIN was formed in 2005 as a logical and coordinated continuation of this trend. 

So in this sense, while the existence of OIN remains significant, its importance has actually declined even as the number of patents committed under its banner has grown. Why? Because the power of the taboo has become even stronger, and woe betides anyone that breaks it. From this perspective, Microsoft’s joining OIN is more a recognition of the inevitable, and the legal recognition of a reality it has already acknowledged it is subject to.

Finally, it’s important to note that Microsoft is not only giving but getting as well. As the value of its old operating system monopoly has eroded, it’s had to spend more of its resources competing head to head with other market leaders who had a head start in open source. Today, it’s future depends on claiming a meaningful market share of new platforms like cloud computing. It has plenty of competition there, and those competitors own plenty of patents.

So unlike the old days, when Microsoft was dominant on the desktop and the server, It now has far more to gain now than lose by joining the OIN non-aggression zone. Most of the important new technologies rely on the Linux kernel, and the OIN license covers all such projects.

But the benefits of joining OIN go further than this. By officially joining the OIN club, Microsoft gains a stronger right to claim the broader protection of the taboo that covers all open source software, whether or not it utilizes the Linux kernel.

Perhaps the greatest significance of Microsoft’s OIN announcement is therefore that it realized that under today’s marketplace realities, it was already bound by the same terms, and more.