[dreamfactory2]

Going a bit off-topic here but open source is partly a cultural test. There are great programmers who are 9-5 and there are terrible enthusiasts, but involvement does mean that people are going to be speaking the same language to a large extent - and the biggest overhead in delivery teams is usually communication.

[jit_hacker]

In fairness, there are a lot of great programmers who work on projects they really believe in and spend all of their available free time dedicated to them. Even if they're for the company/enterprise/startup they work for.

[pjc50]

Are they by some chance mostly male, under 35 and without families?

[TorKlingberg]

Yes, but so are most programmers that do open source work or side projects in their spare time.