Jeremy Garcia, Linuxquestions.org
Jeremy set up Linuxquestions in late 1990s. Up to a million members. At each order of magnitude, new challenges. At beginning, focused on drawing participants. Later, you have to manage a huge user base.
Don't jump in to answer every question. Trust other people to answer, so you build up a community of responders.
Don't focus on building traffic: quality is important. Set the tone you want at the beginning.
Linux and open source communities often known for being rough. Jeremy set a more accepting tone and enforced it from the beginning.
Encourage someone to be first--everyone tends to wait to jump in. When you do find a good contributor, make sure they have the tools they need to do what they can do.
If you grow bigger, you need compartments. Different forums on Linuxquestions have different feel, vibe. You don't need a single giant culture.
Conflict resolution: want to foster free speech, but make sure it stays constructive and respectful. Some people are easily offended, so deal with each conflict individually and put yourself in the shoes of the people involved. But be consistent: if someone feels that someone else got away with something he couldn't, he will resent it.
After community has lasted a while, people resist change. Someone quit once because Jeremy tested a new feature without asking permission. So be careful with changes. On the other hand, Jeremy is not afraid of change, and is planning a major redesign. Just keep the members as part of the conversation.
Now, many sites such as StackOverflow provide alternatives to Linuxquestions. The difference is that other forums are conversational, but Linuxquestions focuses on just providing an answer. Both are useful.
Spammers are a major problem. Linuxquestions has developed metrics and tools, many of them released out in the open. Requires a lot of tuning.
Reach out to regular contributors and ask what they would like to make the community more effective.