“… a fifty-year trend in this country toward less engagement by US citizens in their communities.”

What will be the inflection point where this trend reverses? Could an idea based off Meetup and other social sites enable people to gather around a do the work the community needs?

Community? Call to action. What needs to be done? Define the people impacted positively and who is able to help with skills, talent, time and money. The site could bring people together and help community leaders rally people in and around their communities.