Channels are an easy way to group related content. You no longer have to search or browse the listings for individual bits of content, you can just locate a channel that has the content you are looking for. When there is no such channel yet, just create your own and add as much related content as you can find. People will like you for it!
The first versions of the channels will have a limited number of maintainers, so we can test and tweak it without affecting too many people's channels. When we have fine-tuned the feature, we will open it up for everyone to use.