If you decide to run ad units as part of your blogging income, you need to determine where you are going to place them. If you are being paid by the placement then you should have an agreement as to where that ad unit is placed. If you are running affiliate or PPC ad units, then placement can have a huge effect on your results.
With pay-per-click (PPC) ad units such as Adwords, you will need to play around with the various types and placements of your ad units. The most popular is generally considered the 300×250 text/image ad unit placed within the body of a post. However, different blog layouts will require testing to see the best placement.
When testing ad unit placements, give each placement a reasonable time frame. Ten days is probably a minimum to test for effectiveness. Make sure you record the ad units placement and number of clicks and income received. After ten days, move the ad unit to another place and test again.
One mistake that many bloggers make it to decide on an ad unit and test it in three or four places. They then select the best out of the three or four and run with it. You nay be losing a lot of blogging income if you quit your test regime to early.
You should test in four or five different places on your page, and you should test several different ad unit types including the text only ad units.
If you want to capitalize on any possible blogging income, you will need to test, retest, and test again until you find the best ad unit and the best placement for that ad unit.
