MySQL hasn't always been open source. And it's not clear that proprietary software will help it any better now than it did in the past.
As I'm occasionally reminded, MySQL didn't start out as open source. In fact, MySQL's original license was very similar to what it is trying to achieve today: Free for noncommercial use, but not-so-free for commercial use. It didn't decide to go open source (GPL) until 1999.
So for those of us that get caught up in MySQL's decision to keep some extensions closed to paid subscribers, perhaps a refresher course in MySQL history will make it seem a bit less shocking. (Also be sure to check out the early 2001 brouhaha over trademark violations surrounding MySQL.org. Fascinating stuff.)
With that said, there's an ongoing tension between commercialization and adoption that MySQL (and all commercial open-source projects) have to manage. As a friend noted in an email to me yesterday:
Remember that Monty [co-founder of MySQL] chose to go open source only after the world totally ignored his work. There is a real value that goes along with being open source that lends itself well to adoption. If you have to pay, then that will deter adoption of immature products in ways that it won't with free products.
His take on Monty's reasoning is a bit strong, and I don't agree that MySQL had been ignored, but still he has a point: Open sourcing one's code can lead to far greater adoption in a short period of time than proprietary source.
The question, however, remains for all open-source projects: Is it fair or productive to close off the code after open source has made it popular?
It's not as if the grass is brilliantly green on the commercialization side of the fence, either, as my friend goes on to point out:
This is the crux of the MySQL/Sun commercialization problem: They can't make the enterprise version diverge or they lose the adoption benefit, and enterprise sales are still long, high ceremony and costly.
Perhaps a little empathy, rather than blame, is therefore in order for the MySQL management team as they try to figure out how to trade in some of MySQL's popularity for a bit more cash. It's a fair desire but it's by no means obvious that closing off some extensions will accomplish this. The MySQL team is experimenting, as they've said. Let's cut them a little slack (while still remaining open-mouthed and open-minded).
Commercializing open source is a tricky balancing act, as open-source Funambol's name suggests (Itmeans "tightrope walker"). For MySQL, it's a "tightrope" it has been walking for more than 10 years, which decade has seen the company on both sides of the open source/proprietary divide.
Ultimately, the only thing we know is that Marten, Monty, Zack, and team mean well and generally do well. They seem to balance better than most.