The deep irony about designing a community is that it's ultimately not about the buildings; though the built environment certainly does affect us quite a bit. It's about the people!
Cohousing is, at it's heart, about people choosing a more collaborative way of life. The Common House and sharing meals is the heartbeat of cohousing. The built environemnt is explicitly designed to reflect the needs of the people. Often other forms of cooperation evolve, like car sharing, child care, etc. The AARP is very interested in how cohousing addresses issues of isolation and poor nutrition for seniors.
My husband and I are looking for a cohousing community to move into in the next few years, hopefully one we can sell our current place and have enough for a downpayment.