Stephen O’Grady del.icio.us’ed the inaugural post of the new blog, and his comment was “biggest community wins”. It’s true that the size of a community matters, but it’s not as simple as absolute size. Communities need to reach a point where they become resilient and self sustaining.
That means you need people, and you need enough of them so that there can be an reasonable distribution of work – if one or two people are doing all the work and there are lots of bug/feature requests, then that’s not a reasonable distribution of work. I’ve heard this called ‘scalable’ but it’s not necessarily the case the communities need to scale to accommodate lots and lots of users, but it does need to support its user base well, and the key to that is to share the work.
Another way of measuring the reasonable sharing of work is to look at the “hit by a bus” number – the number of people that would need to be hit by a bus/truck/etc in order to make a substantial impact on the sustainability of the community. If this number is “1″ or if there are multiple “1″‘s, then that would be another indicator that the community hasn’t become self-sustaining.
Communities (like marriages, I suppose) that can’t fight well, can’t stay together. So another indicator of a healthy community is the ability to have and resolve conflicts. This is especially important, but often left un-stated as an important quality. It is important for communities to have diversity of opinion and approach, and if they do, conflicts will inevitably follow.
Also related to conflict resolution is the ability of a community do deal with difficult people – Ben and Fitz have a great talk on this [PDF], and it also contains some good content on what makes a healthy community.
So these are just a few of the other factors that influence the quality of a development community.