There's quite a flurry, in the blogosphere, of discussion about the notion of "open core" software. Some see a threat, like Simon Phipps' "Open Core Is Bad For You"; Matt Aslett urges some perspective on the debate, reminding us that "Open core is not a crime," and in a comment there, Mark Radcliffe worries that venture capitalists might be put off by "open core demonization."
These are all smart, experienced guys, but they seem to be running in different directions. Makes you wonder if they're all thinking of the same thing when they say "open core"! Maybe we need to work that part out, first.
I think what we're missing here is an exploration of the delicate line between "crippleware" and "added value." If your so-called "open core" product isn't quite up to the job at hand, if customers really need to buy the commercial license in order to get functions they need to execute the basic goal of the software, then you deserve the "faux-pen" label and shame.
But, on the other hand, if the open parts accomplish their goal fully and well (and, of course, if they're truly open, to contributions and priorities coming from the community), then the open-source product deserves to be assessed on its own terms. If there are also commercially licensed, or even proprietary/closed things associated with it that together accomplish some larger goal, that's a different product, not a betrayal of the open one.
In between, there's naturally some gray area we can debate to exhaustion, but a clearer idea of the purest distinction might help.
Obviously, CollabNet occupies a particularly clear-cut corner of this space. The Subversion project, initiated and supported by CollabNet for nearly a decade, is unquestionably "open source." The project sets its own direction, listening to CollabNet's needs but completely open to other ideas. And while much of the guidance and labor have always come from CollabNet, much as well (and in truth, more) comes from the many non-CollabNet contributors. There's no "faux" in Subversion's "open source."
At the same time, though, it's undeniable that Subversion is crucial (dare I say "core"? to CollabNet's mission. And in addition to Subversion and a number of other open products, CollabNet certainly does have non-open products, often built directly upon these open-source foundations. Does the existence and completely proprietary licensing of CollabNet TeamForge make Subversion somehow "faux-pen"? Hardly!
What I think would better frame all this is an expansion of the "open core / open complement" dichotomy (for which, I believe, Matt Aslett may take some justified credit). The category of "something crucial to the larger product, and yet also fully useful on its own" simply doesn't fit neatly into the "core/complement" split. Lumping these cases in where they don't belong just creates confusion. And when, like Simon Phipps, you have strong things to say, you want to aim them with clear categories.