Laszlo Systems has shifted from selling closed-source software (their Laszlo Presentation Server), to selling services around open-source software (their newly-opened Laszlo Presentation Server). I always wondered how they would manage to compete with Macromedia's Flex platform, which occupied a very similar niche (rich web-based applications).
Now they're hoping to succeed with open-source mojo, and more power to them. I haven't used either Laszlo or Flex, but they seem very powerful and eye-opening in terms of the types of applications they can build. I hope it works for them.
Oliver Steele is an insider with more details. He's also a fellow Brookline resident, though I haven't (yet) met him.
I've never worked on a large open-source project, but I've wondered: do you write the code differently when you know it will be viewable by the world? Does working in a glass house change your code? As a coder, I like poking around in other source packs, and I'll be downloading Laszlo to see what the code looks like (though it's a lot: the .tar.gz file is 107M!)