When you put a WifiBox at the edge of a WifiNet's range, you extend the range of that WifiNet. The WifiNet will be a patchwork quilt of WifiNet 's that could eventually, and in a grass roots fashion, cover the earth. (see OhReally )
There is a minor glitch with this formulation. The major deterinant in bandwidth is actually not distance (unless you're crossing oceans or going to the Moon and back). Instead, it is how many hops the packet has to do. Each hop adds a latency step (I dunno how big).
The present design of the wired Internet is tree-like: any leaf is just a few hops from a major trunk, so anybody can send a packet to anybody else in a few hops, and you need trunks (or thick pipes) to do that. Otherwise packets take forever to get anywhere, and you end up looking like a 300-baud modem. Or so say the gurus of comp.os.linux.networking, anyway.