I'm just setting up my AdSense account and I'm not quite sure what to do for "channels". I read the "Optimizing with Channels" page, and still don't know exactly what to do here.
dude channels speciallised for ur domains if u have more than one domain u can dedicate a channel for every domain to show u impressions, ctr, clicks
those are url channels. There are also other channels which show statistic of each ad format (of course if you add channel to this ad).
For instance, you could have a channel named 'top of homepage' and another channel named 'bottom of homepage' - in each of these channels, you would store the ad for that respective section.
most people have multiple site running several adsense ads. you can use channels for each ad code you generate and can name them the way you want. for example, for the right menu ad on site abc.com, you can name the channle something like "abc-right" or something easier for you to know. so when you get clicks on your ad, you know which one of your ad code got the clicks. this kind of tracking is important as they help you further optimize your site/ads
By using channels, you can do the experiment in your site. You can monitor the performance (i.e. clicks) of different ad units within a period of time. After that, you can use different combination of ad colors and formats, and determine which ad combination is better. After several rounds of experiment, you can then find the best ad combination that can yield the best result for you. http://www.dagsensecodes.com/2006/12/what-is-adsense-channel.html