Best Performing Banner Ad Sizes

If you are an online publisher making money off advertising, how do you decide which ad formats to display?

Marketing Sherpa, a website specializing in online marketing, did some research on which IAB standard ad sizes got the highest click-through rates.

(Chart and conclusions after the jump.)

The chart shows some interesting takeaways:

1. Low click-through rates overall

With an average of only 0.21% of impressions generating a click, display ads are generally low performing. Marketing Sherpa points out:

Online ads are branding tools. Direct clicks are simply a happy byproduct. In the context of direct response, online ads appear to be, at best, moderately successful.

2. Larger is slightly better

The largest ad sizes -- 728x90 leaderboards and 300x250 rectangles -- perform above average.

They are also the top 2 most popular ad formats according to Nielson (Sept 2008).

It's possible the higher click-through rates are due to placement since these two large ad formats are typically used above the fold (eg., in the header of a website). Note that these are the two ad formats used here at About.com above the fold.

3. 468x60 banners perform the worst

The oldest format, the original banner size of 468x60, performs the worst! It may be due to the fact that users have learned to ignore ads of this size. Another possible reason is that because it's smaller than other formats, the 468x60 is typically buried within content, and not given prominent placement like the 728x90 leaderboard size.

via Lightspeed Ventures