A channel is nothing more than a member's profile. It contains basic information about that member, including submitted & favorite videos.

You can think of channels just like you think of them on TV. They provide you with episodes (screencasts in this case) about several topics. On TV, a channel may focus on any subject or industry. On TechieVideos, a channel may be a company or individual, and focus on any topic from video games to computer programming to gadget hacks, or just cover a variety of random topics. It's up to the channel (member). Consider it your personal online TV show.