A channel is like a play-list or content-schedule which people in a group can collaborate on, but can also exhibit many other specific associations such as venue and equipment. This can be used as a means of organising lectures, presentations or private media channels.
A kind of unification is taking place in the web applications arena where everything is starting to be seen as a specialised instance of the general "channel" concept. One technology that really started to move this concept forward was XMPP which provides the underlying communications and networking support for high-level functionality such as publishing and subscription services, chat clients and notification systems. As of 2016 there are even more high-level technologies available for the underlying transport between arbitrary nodes over diverse networks such as ZeroMQ (or maybe the NanoMsg fork) or Telehash and Hyperboria which have been designed specifically for mesh networking.
In 2009, Google took this concept even further with their Wave concept which is essentially a unification of email, chat, blogging and wiki which is defined as an XMPP extension (XEP). And now as of 2013 this general technology movement of unification is starting to spread even more and the next generation of social network looks likely to be in this form, for example Red, the new version Friendica is explicitly built on the idea of "everything is a channel" and is built on Zot which is itself a key technology in this area specialising in secure unified channel-based communications over many diverse protocols.
Another important aspect of our project here at Organic Design is that the technology we use for our system needs to be secure and peer-to-peer. The technology of the net is also now very much headed in this direction with technologies like Bitcoin, Namecoin, Zot and Bitmessage being of particular interest as they're not only peer-to-peer and very secure, but also are based on the "everything is a channel" concept.
Organic Design's ideal channel system
What we'd like to see channel evolve into that would most help the vision is a kind of extendable Wave-like functionality that's completely open and operates fully in peer-to-peer space rather than in a federated centralised-server paradigm.
The functionality of this peer-2-peer wave-like application should have all the usual fundamentals of channels such as general communications, subscriptions, playlists, blogs, social networking etc but also include the ideas of booking resources and managing storage and distribution (which is actually a very similar requirement to channels as it's all about bookings and schedules). This idea relates to the Wave concept similar to how Wiki Organisation relates to the wiki concept.
With the channel mechanism giving us the technical ability to communicate, trade and organise our resources together, the only thing remaining is to move our own site and system out of the wiki and into the channel technology so that we can then begin making our concepts such as trust group and platform into active channels rather than just static ideas to ultimately form the platform network.