These channels is a rather established concept of "collision safe" channels.
Simply put, some malicious person may not gain operator privileges on an existing channel by means of a server reboot or netsplit.
Technically speaking, this is achieved by assigning each irc server it's own id. This id is the prefixed to the true channel name, making the channel unique across the network. This is then linked to a short name (or dynamic name if you like), to allow easy access. If any malicious person attempts to join/create the same channel on a split server, that channel would have a different unique name (since that server would have a different id), and although he/she would gain operator privileges on that channel. When the net merges, the channels will not, meaning the malicious user won't get operator privileges in the first channel (in fact, he/she will not join that channel at all).
For further reading, please see
http://www.ircnet.net/tech_docs/ircnet/!channels.html (sorry, can't make the link proper, seems to break the post in the forum. Exclamation mark should be there though...)