It's a collection of encrypted tunnels that link together a variety of private LANs and turn them into one larger network. It's essentially a mini-Internet for folks that already know and (usually) trust one another. This is cool once you realize that this is much like the Internet looked circa 1971 or so. The MetaNetwork allows us to play with interesting things without actually doing it on the Internet. One prime example is our anycast authoritative DNS server for the .prv TLD and reverse lookup zone of the RFC 1918 addresses.