Networking over USB

[Grok Mogger <linuximp@gmail.com>]

I've seen some writing on the internet that suggests that it's 
possible to do networking over USB.  Like I could send TCP/IP 
packets over a USB cable instead of an ethernet cable.  Is this 
actually possible?

If so, I don't know where to even begin.  I'm not finding much 
googling.  Could someone please give me a place to start?

Thanks,
- GM