They are independent in all ways save for sharing the information on availability of discounts to the group. Easy to join. They operate as a Level I Community, save for their proximity to each other. Relocation to the community locale and acceptance into the network is generally the only way to join. The land is generally owned by the community as a whole, through individual shares.
Members reside on and work in, for, or near the community.
Power, water and communications are often internal or capable of becoming internal. Sometimes set up as a corporation or non-profit organization. Membership usually, but not always, requires approval and specific talents or specialties. Relocation is generally mandatory.