Well, I am not ready to become a moderator again. Have some business efforts going on that I probably need to give priority to. Also, I am kind of still have a foot in both forums.
In general though, I think a working forum does need:
1. To be tied to a news site to constantly attract new members.
2. Needs to be open to new members. As older members invariably post less over time....it is the constant influx of new members that keep forums going. This has been the challenge for all of them.
3. Needs to moderate only lightly.
4. Needs to draw an international crowd.
5. Needs to have a several people regularly starting new threads.
6. Needs to avoid the tendency for two or three people to dominate the discussion and direction of a forum (for example, mostly pro-Ferrari or mostly anti-Ferrari, or mostly pro-Hamilton or mostly anti-Hamilton). These "group think" tendencies ends up creating half a forum as people with opposite views leave. Not sure how one patrols that or controls that, but this has been a problem on several forums I have seen.