Thank you, Will, for all this information!! I did not know about Custom channels, URL channels or Heat Map for example :angel:. I will bookmark this thread, at least I will have something interesting to do during the weekend.
Time for a boost to this thread ...
Check out the best performing Ad Units according to Google: https://support.google.com/adsense/answer/2953032
Also, be aware that you can create mobile responsive Ads that adjust in size according to the width of the containing DIV which is very cool I think. So a mobile device may only have a 320 pixel wide view port, yet a desktop can be HDTV size or more. But with the mobile responsive Ad you can serve both with one Adsense code block.