If you implement, for example, the network stack as a filesystem, and you have generic facilities which let you bind "files" from one system to another, you can forward your traffic through another host as easily as:

    import remote-host /net

Now your new network connections will go through remote-host, because a network connection is just reads and writes to files in /net.

Lots of neat applications when you take a few simple ideas and expand them as far as you can: represent everything as files in a namespace, provide advanced tools to manipulate that namespace, and do it all via a networked protocol.