Anyone here can tell me some about google_ad_channel? I actually want to know what its function. Thanks in advance
A Google add channel is simply a label. You create it inside your Google account in order to be able to see impressions, clicks, CPM and earnings from a particular ad placement on your site - or perhaps a group of ad placements. For example - you may place an google add in the upper right of your page - you could create a channel "upper_right" - then you would be able to see how that specific placement performs. It does not have to be limited to a single placement - it could refer to the same position on multiple pages of your site - or it could be something far more abstract that you are interested in tracking. The bottom line is that it is a label - or category if you will - that allows you to separate out and track your earnings and understand them more precisely on Adsense. Side note is it's still kind of amazing how few of the other major networks have adopted this very useful and simple concept.
Thanks for your reply (+ rep added) so is it ok if i put google_ad_channel "" instead of google_ad_channel "xxxxxx"? i mean is it NECESSARY to have a number set there?
Google ad channel enable you to view detailed reporting about the performance of specific pages and ad units. When you create a new ad unit, you can attach a channel to it, so that you can see the performance preport based on the channels next time when login Google Adsense. You can give a channel any name that meaningful for you when you create a new channel. See here for more detals.
Its a tracker that tracks clicks from certain adsense ads, allows you to see which ads perform the ebst
Simple answer: No it's not required that you have an ad channel. It IS useful for statistics and similar though..