Dave highlights this post by Rob Seaton. Rob believes communities decay as they grow larger. I've included his summary below.
- The development of trust and kindness between two people depends on the probability that they will interact in the future.
- When communities grow to a certain size, people no longer expect to interact in the future, and thus are more likely to defect – to be petty, mean, aggressive, and to put little effort into their contributions.
I disagree with both points.
As communities grow larger, the sense of community dissipates. This leads to lower levels of participation unless sub-groups are nurtured. However, sub-groups are rarely nurtured well within communities.
As communities grow larger, they attract people outside of the core interest. Those without connections to existing members. These people are more likely to be deviant. You also attract those with antagonistic personalities. If you have a community with 1000 members, 10 are likely to be antagonistic.
This minority exhibits behavior which attracts undue attention because it deviates the most from the norm. This doesn't reflect the behaviour of the entire community. The personalities of people in a community rarely change, but the people in them do.
You can counter this decay by properly socializing newcomers into the community, facilitating sub-groups, and rapidly removing the antagonists from the community.