Can someone explain sub-channels?

The sub channels are described in the default current.conf as being "live"
doc. What exactly does that mean?

Is there a way to access these sub channels?   Is there coding that needs to
be done to get sub channels working?  For my purposes I *really* need to
have access to the subchannels.

Any information you could send that would help me get started on code
change - if changes are necessary/possible - would be appreciated.

I just switched my profile from the digest mode to individual messages so I
you have comments could you cc: my email directly for today so that I see
the messages?

[email protected]

Thanks, Andrew