There is Kingdom power when the body of Christ comes together to show the love of Jesus in practical ways to it's neighbors. Movements like this one in the video with Engage Atlanta and even others with whom I've worked with such as Unite Atlanta are making a significant impact for the Kingdom of God.
A couple of thoughts I had as I watched this video:
This demonstration of Atlanta churches working together isn't a result of some initiative, top-down from some organization. Rather these endeavors often come as a movement of the Spirit, and grow from the bottom-up.
Also, it is important to ask the community what they need, rather than assume you know. Too often we come to serve others with presumption and perceiving what we think is best...rather we need to ask in humility and discover how to serve their real needs.
No one person, or church or organization is flying their banner - rather it is the banner of Christ that is being flown- which means God gets the glory, not us.