[runT1ME]

>This is how most open source software companies make money. This usually includes some horrendous subscription fee and guaranteed SLAs. I never quite understood, why this works. My only explanation is, that many customers are comfortable with this, because this is what they are used to from buying proprietary software.

I think Jonathan Schwartz had a decent answer to this question. It was basically that there are two types of customers, the kind with more time than money, and the kind with more money than time. If your company stands to lose thousands of dollars for an hour of downtime, minutes, isn't paying a subscription fee with 24 hour support worth it, even if it's almost never utilized?

Another way to make money is to backport bug fixes to previous versions that customers are on. With companies who have more time than money, this won't bother them, they can compile their own versions and do their own merges of bug fixes. For companies making boatloads of cash, why waste developer effort doing this for a negligible fee?