I found myself thinking about my experiences with on-line community building and found myself frantically scribbling margin notes.  After mulling this over for a few days, I came up with four basic “rules” that seem to apply whether creating on on-line community for poultry enthusiast in 1995 or launching a corporate Facebook presence in 2012

1. What’s in it for me?-  The unspoken question at the heart of all on-line communities.
2. I don’t want to be the first person on the dance floor – If there is no conversation, people will pass on by.
3. Is the cost of using the technology less than what I get out of it?  - Great technology won’t make a community, but bad technology will kill it.
4. Are the trolls under control? If the community feels safe, people are more likely to extend themselves and participate.  A strong community builds a sort of immune system against abusive members, while a weaker community can really suffer.

With on-line communities this is driven by the vision of the community sponsor – who or what ever makes available the concept, technology and oversight.  The unique values driven by the concept create the value for the users, which in turn will lead to an active community.  The perceived quality of the technology typically evolves along with the state of the art for the genre.  If a community is built on software that is poorly designed, lack the features users expect, or just plain doesn’t work reliably, the community will suffer.  Finally, the rules of the community and the quality of the moderation will determine whether the community feels safe.