When we talk about communication or marketing channels, we’re really talking about all of the different avenues available to reach the target audience(s).
A list of possible channels might include email marketing, direct mail, social networking (MySpace, Facebook, LinkedIn, Twitter), blogging, online search features, advertising, article/editorial placement for educational purposes (in industry trade or consumer media outlets), exhibiting and conferences or trade shows, face-to-face communication, etc.
Integrating channels into an overall campaign isn’t simply about using more than one of the channels listed above.
It’s better to think of “integration” as incorporating a “multi-channel” approach to the campaign at hand.