Darren at ProBlogger has a great roundup of advice on ideal ad placement to maximize click throughs when using Google Adsense. Probably the single most important point he makes is that content placement is just as critical as ad placement. After all, if you design your site around your ads, you won’t have many readers. The content is why people read your blog; the ads should be visible but not the main focus.
I’ve learned a few things about ad placement by experimentation. Of course your mileage may vary, but here’s what works for me.
1. Image ads convert better than text.
An image has something to show, and is easier to see. Whereas text ads must be read, visual ads present themselves more naturally to the eye. They are also colorful, and often animated. In addition, the entire image area is clickable, unlike the relatively small region on text ads (a change made by Google to reduce click fraud).
2. Trust the algorithm, don’t blacklist.
It’s tempting to cull certain ads from appearing if you think they are way off-topic (or outright annoying). But there’s method to the madness. I’ve found that if I start excluding URLs for certain advertisers too aggressively, my CTR drops pretty dramatically. The adsense algorithm learns over time, so you need to let it learn what ads work and which don’t. That requires patience. The longer you have ads on your site, the better the matching will be.
3. Bigger is better.
This is a fairly obvious one. A banner (768×90), wide skyscraper (160×600) or medium rectangle (300×250) is always going to attract more attention. It’s also worth mentioning that these larger formats are the ones with more color, animation, and even video and user interactivity, all of which get the reader’s attention.
4. Complementary, not competitive location
This is one of the more important (and subtle) issues. I go against the grain in that I believe it’s unwise to put ad units within a block of content. There are several distinct regions or “content elements” within a post: the post itself, the comments, header, footer, navigation, etc. It is easier on the reader when ads are placed interstitially between these content elements. The placement of ads should complement the reader’s visual flow, being visible but not smack-dab in the middle of the natural path that the visitor’s eyes follow.
I am also skeptical of heat maps that purport to tell you where a user’s attention is drawn first, or lingers, because I think that what matters more is the reading trajectory over the page. It’s critical to keep content elements along that reading trajectory, and any ad units on the page should be adjacent to that trajectory, providing an easy “on-off” side-trip from the main path. I think of this as rest stops on an interstate – the best ones are the ones where it’s easy to exit the highway, take a break, and then get back on easily – that way there is minimal interference to the journey. A reader visiting the site is a traveler in much the same way.
I’m no expert by any means (and I make about $.25 a day from Adsense, because none of my blogs are highly-trafficked). However I do want to mention my own blogs as examples of the guidelines above in action: City of Brass and Nation-Building, both hosted on Blogspot. As you can see, they have a wide column of 300×250 medium rectangle ads down the right side. There is also a 768 banner at the bottom of the page. I may experiment with a half-banner in the upper right corner as well, but the main idea is that the ads are large and to one side, leaving the content area almost entirely whole.
Another point to make is that I use the old template system on these blogs, not the new blogger version, because I find that it affords me more control. Most of the sidebar widgets available on the new beta system are useless for my purposes and would only eat into available ad space on the sidebar. It’s really just an ad-bar attached to a single-column layout, not a genuine sidebar – some of the content like links to my archives, etc that would normally go into the sidebar are now actually at the bottom of the page.