Pierre notes it is "only a matter of time before an open source company decides patents could be used to solidify open source dual-licensing schemes." I think he's right. In fact, I've seen this very issue rear its ugly head within my own company as I've thought through ways to partner with Microsoft and other proprietary companies.
It would be very easy to do as Novell did: Enter into an agreement to make a version of one's software "safe" from patents. It makes Microsoft happy. Presumably it makes one's users happy ("I'm safe from...my vendor and its partners?!").
But it doesn't fix the downstream problem, and it doesn't fix the broken software patent problem. It trades off FUD to make a sale. Myopic and ultimately damaging to one's customers, one's peers, and oneself.
This isn't even remotely intended to be a criticism of any one company or group of companies. It's rather an acknowledgment of an issue that is going to become more and more pronounced over time.
At Alfresco there is no functional difference between our Community and Enterprise products. We invest more time in testing/stabilizing Enterprise and bug fixes go immediately into Enterprise but are delayed into Community, both because this is a service that people pay for and because we'd love to see our Community self-serve as much as possible. It's healthy for our community to be able to thrive without us.
The problem with this sort of distinction (which we and virtually every open-source company of which I'm familiar espouses, in terms of a "community" and "professional" version) is how easily patent protection could creep into the one but not the other. When the open-source world starts selling the same FUD that the proprietary world does we have lost.
I care far less about hybrid models that depend on a mixture of proprietary extensions and an open-source core, as MySQL is contemplating, than I do about hybrid models that are a blend of "open source and very risky!" and "proprietary and oh so safe!". If we slip into this sort of a model, open source loses its potency. It loses its character. It loses its integrity.
The downstream must be preserved. The right to fork without needless concern for patent time bombs must be preserved. Let's be careful about falling into this seductive trap that Pierre points out.