I split tested 3 separate regions of my site and looked mostly at eCPM to compare them. If you aren’t sure what eCPM is click here. I think it’s better to use eCPM than click through rate (CTR) because it incorporates not just how often it’s clicked, but also how much you make per click.

Right Aligned vs. Left Aligned Ad In Post Body

This ad region makes the most money for me, and was smack dab at the top of each individual post page (but not on the homepage).

• The right aligned ad got a 0.78% CTR and $1.41 eCPM
• The left aligned ad got a 1.30% CTR and $5.31 eCPM

Clear winner: left aligned (276% improvement)

It’s hard to say why this is exactly. Maybe the left aligned ad looks more like it’s actual content instead of an ad. Whatever the reason, the difference was substantial.

Top Right: image vs. text

This ad resides at the very top right of every page. I had been running it with image ads for a while and decided to test it against text ads (with some appropriate color choices).

• The image ads got a 0.35% CTR and $1.74 eCPM
• The text ads got a 0.33% CTR and $2.15 eCPM

Interesting to note here that although the CTR went down slightly, the eCPM went up. This seems to indicate that the text ads were paying more per click. So even though it was clicked slightly less often it still made more money overall.

Winner: text ads (narrowly)

Under Posts: image vs. text

This ad was placed at the bottom of each post page and also on the homepage under the excerpts. I again decided to test some text ads against the incumbent image ads.

• The image ads got a 0.58% CTR and $1.86 eCPM
• The text ads got a 0.43% CTR and $2.27 eCPM

Again here the CTR went down and the eCPM went up. Also worth noting is that the color scheme I used on the text ad block is consistent with my site. “Blockquote” tags on my site use a similar color scheme.

Winner: text ads