Does Ad Size Matter? It Depends What You Do With It

If you’ve visited the homepages of Yahoo!, AOL or MSN in the past couple of months, you may have noticed some really big banner ads. The online publishing industry has been experimenting with new ad sizes and formats lately, and it’s led to some very eye catching advertising.

On the left is the ubiquitous "Medium Regular" banner ad that Kohl’s ran on the MSN homepage. On the right is the same ad, which ran on AOL in larger format.

As you might expect the larger ad got many more clickthroughs, even as a percentage of visitors who saw the ad. But so what? Kohl’s doesn’t want to sell page views to people who see their ads, they want to sell blenders. And that’s where the story gets interesting. You might not expect it, but the small ad actually performed 1.7 percentage points better in driving purchase.

Perhaps that’s not surprising because once someone clicked through either ad, they ended up on the same landing page. In other words, the larger ad drew the attention of more would-be shoppers, but the smaller ad found a greater concentration of motivated buyers.

Which ad size worked better? That depends on Kohl’s objective – were they after attention or conversion? Both ads demonstrated strength.

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