I've been saying this for a long time-- the strategy is not to try to build your own communities it's to join the communities where they are already gathered. This new study by Ed Moran of Deloitte provides the exclamation point: Why Most Online Communities Fail:
Thirty-five percent of the [corporate] online communities studied have less than 100 members; less than 25% have more than 1,000 members - despite the fact that close to 60% of these businesses have spent over $1 million on their community projects.
I know I must sound like a broken record on this point, but the message just isn't sinking in. What's it going to take for people to "get" this? A million dollars or 10 million dollars. It doesn't matter. The people are not coming. You have to go to them. It's pretty simple actually.