Google AdSense enabled AdSense Channels back in March 2004 to give publishers a more controlled method of tracking ad performance. Since then, they have expanded the use of channels for that purpose.
Since then we really have not discussed the different methods of using Channels to track efficiently and accurately.
A WebmasterWorld thread has a collection of methods of using channels to help publishers track their advertisements success.
Here are some channel strategies mentioned in the thread that you can use for your AdSense campaigns:
- Ad Type Channels (is it adlinks, search, adblock) and always defining size and kind of the ad IE: "adlinks 4 ads 728x15"
- Language Channels (to track what users are making you earn money) IE: "spanish", "french"
- Position Channels (where is the ad positioned on page) IE: "top", "left column", "bottom"
- URL Channels (what page is paying) IE: "mydomain.com/home", "mydomain.com/product1.asp"
- Color Schema Ad Channels (what color palette are ads using, you can put palette's name or description) IE: "contrast, red", "mypalette1", "site similar look and feel"
- Visitor Type Channels: Loyal users, new users
- Ad Size Channels, to define the various sizes of ads and see which works best
Those are just some of the AdSense channel methodologies used and discussed in that forum thread.
Forum discussion at WebmasterWorld.