Which Custom Channels Should You Create?

With the range of Custom Channels limited only by your imagination, it’s not
always easy to figure out which channels you need to create.
I’d recommend that you build channels based on the following:
Location
Do ads do better at the top of your blog pages or on the side? Do you
get more clicks from ads that you’ve slipped into the article or from
the ads at the bottom of the page.
Try creating different channels for each sort of location so that you can
track how different locations are doing.
Ad Unit
Different ad units can deliver different results. You might be using four
or five different types of ad units across your sites. Make a channel for
each type of unit so that you can get an idea about which units are the
most attractive.
Of course, location and ad unit are related but you won’t be able to
untangle the data unless you have it!
Color
I keep saying that the color of your ads should match the color of your
site. But not all your sites are the same color! You might well find that
some color schemes win you more clicks than others — a fact which
could influence your overall site design.
Create different Custom Channels for different colors and you’ll have a
better idea of how your designs affect your income.
Link Units
It’s certainly worth creating a channel to track the performance of your
link units. These are special in their own right and you should know
how they perform in comparison to your other ad units. AdSense now
delivers this information separately but you should also be creating
channels for different link unit placements so that you can see how the
units do in different locations on the page. That will also let you
compare the performance of a link unit to a regular unit placed in the
same spot.