Bruce Chant tackles one of my favorite concepts, the long tail (For work we're devloping on a long-tail content management system. Not Ekklesia our church content management system.) and discusses it's implications for church planting:
Within my own city, you see “niche’s” of people everywhere, not just geographically, but in terms of demographics, lifestyles and values. And where these niches exist so to does opportunities for new churches to be planted in order to take the good news to these people in indigenous forms. The more new churches and the greater the sum of these churches the greater the total, overall impact for the Kingdom of God. That is the effect of the Long Tail and the power of church planting.
Full Article at his blog: The Long Tail and Power of Church Planting