Guy Kawasaki interviews MySQL CEO Marten Mikos:
Question: How do you make money with an Open Source product?
Answer: We start by not making money at all— but by making users. The vast community of MySQL users and developers is what drives our business.
Then we sell an enterprise offering to those who need to scale and cannot afford to fail. The enterprise offering consists of certified binaries, updates and upgrades, automated DBA services, 7x24 error resolution, etc. You pay by service level and the number of servers. No nonsense, no special math. Enterprise software buyers are tired of complex pricing models (per core, per cpu, per power unit, per user, per whatever the vendor feels like that day)—models that are still in use by the incumbents.
At MySQL we LOVE users who never pay us money. They are our evangelists. No marketing could do for us what a passionate MySQL user does when he tells his friends and colleagues about MySQL. Our success is based on having millions of evangelists around the world. Of course, they also help us develop the product and fix bugs.
And the few times that they say that they hate MySQL, that helps us too because complaints usually contain some good suggestion for improvement.
The rest is just as good — go ahead and read it.