I have noticed that I have some site with ads that have no channel. The earnings , albeit low, don't show in my earnings in my account. I add the ad channel and now it shows my few cents a day. Was I not paying attentions or do your earnings not show if the channel is not set up?
Channels are just so you can keep track of how much money different stuff/sites earns. Also so you can test stuff out like changes to the ads.
If we can want trace more detail, we should be any single site? eg. www.a.com, www.a.com/1.html, www.a.com/1.html. Or just put the main site is sufficient?