As I've written elsewhere, people have realised that there's a bit of a problem with the term "open source". It's becoming too popular: too many people want to stick the "open source" label on their wares without worrying about the details - like whether they conform to the "official" Open Source Definition (OSD).
The real conundrum is this: how can the use of the term "open source" be policed when it has no legal standing, since it is not a trademark. Theoretically, anyone can use it with impunity - for anything. This is obviously a problem for the "real" open source world, which needs to find a way to encourage vendors to use the term responsibly.
Peer pressure is certainly important here, but there may be another factor. In the course of research for a feature, I came across IBM's big patent pledge of January 2005:
IBM today pledged open access to key innovations covered by 500 IBM software patents to individuals and groups working on open source software. IBM believes this is the largest pledge ever of patents of any kind and represents a major shift in the way IBM manages and deploys its intellectual property (IP) portfolio.
Back then, this was mildly interesting, if greeted with a certain cynicism. But today, in the wake of Microsoft's sabre-rattling, patents are much more of an issue for all open source companies, which makes the next paragraph of the IBM announcement particularly pertinent:
The pledge is applicable to any individual, community, or company working on or using software that meets the Open Source Initiative (OSI) definition of open source software now or in the future.
So there we have a major incentive to meet the OSI definition of open source: if you do, IBM will let you use a good wodge of its patents. This means that in the event of patent Armageddon, where IBM and Microsoft slug it out in the courts, you will not only be safe from any direct attacks from IBM, but might even enjoy the indirect halo effect of IBM's patent portfolio.
Although IBM has not exactly guaranteed it would come rushing to the aid of any OSI-approved damsel in distress if it were attacked by the Microsoft dragon, its patent pledge does contain an element of this implicitly. It's certainly easy to see the benefits for IBM of such a move, both in terms of positive publicity and direct competitive advantage. At the very least, Microsoft is likely to think twice about attacking any company that has this kind of patent hook up with Big Blue.
If you don't adopt the OSI approach, though, you're outside the IBM castle, and on your tod when that nice Mr Ballmer comes calling about those patents he claims your company infringes. And since you're not playing nicely with the official OSI crew, don't expect any help from its big corporate chum, IBM.
Now, tell me again why you don't want to go legit with this "open source" label?