Sharing the Internet with a MAN
From the beginning of community wireless, extending high-speed Internet access to someone who otherwise can't get it has been arguably the primary goal. This includes getting totally unconnected people online, transitioning modem users to high-speed, and multiple high-speed users banding together on a fatter pipe.
On a small scale, sharing consists of simply putting up a NAT'd AP and configuring the clients. In order to extend the network beyond the physical range of the AP, you start to get into repeater nodes, WDS, and network routing issues, essentially building a small-scale MAN. A full MAN creates a wireless cloud across the city that allows anyone to jump onto the network simply by putting up a wireless transceiver of the appropriate type. If a smart node is put up, the size and/or capacity of the network increases at the same time.