The fact that banner ad size has an impact on performance may seem intuitive and obvious to some people, but it is not to others.
To be truly effective, advertising has to deliver results for both the publisher and the advertiser.
The results for the publisher come in the form of revenue, client retention, revenue growth and higher Website ad rates. Results for the advertiser come in the form of clicks, leads and transactions.
Following a commonly accepted banner ad size standard will result in more revenue and happier clients. Ad networks will deliver higher quality and better paying clients as well.
Standard Sizes: Universal Ad Package
Many Web sites follow the standards set by the Internet Advertising Bureau of more than a dozen ad sizes. The dominant four — known as the Universal Ad Package — are 300 x 250, 728 x 90, 160 x 600 and 180 x 150.
Many agencies, advertisers and publishers deal only or mostly with the first three sizes. The 180 x 150 seems less widely used than the other three.
Numerous other sizes are widely used, but the above units are the most accepted.
The largest ad network on the planet, Google AdSense, uses the first three above along with a 336×280, 300×600 and 320×100 large mobile banner as its standard banner ad sizes.
Other Web sites do not follow the IAB standards and use their own proprietary sizes.
Related posts: Online ad rates * How to sell online advertising * Advertising ROI
Ad size impacts revenue * Effective ads mix branding and response
Bigger Banners Draw More Clicks
Some sites will run only small button ads, which have been shown to deliver low click and advertiser retention rates.
Sites that follow this approach will have difficulty landing any major account with Web experience and risk losing important revenue opportunities.
For sites that follow product and advertising standards, a common approach is to use the 728 x 90 at the top of a page, the 160 x 600 on the right rail and either of the rectangle ads (300 x 250 or 180 x 150) in the body of the page.
These sizes provide a combination of branding and response that is widely accepted in the industry at this time.
Viewability Matters More Than Ever
A large banner ad doesn’t matter if it isn’t visible to the site visitor because it is displayed so low on the page that scrolling is necessary.
An impression that is served is not always viewable. That lowers the value of the ad considerably and raises the question of why an advertiser should pay CPM rates on a non-viewed ad as opposed to paying cost per click.
Banner ads can be fully viewable, such as a leaderboard at the top of the page; non-viewable when it appears only after the visitor scrolls; and partly viewable, when a portion appears without scrolling, such as a 300×600.
As the industry’s viewability standard becomes more common, it is clear that a partially viewable ad is better than an ad that isn’t viewable. For that reason, large banner ads have a better chance of being at least partly viewable.
Too Many Ads Spoil the Party
As banner sizes increase to attract more views and clicks, a great percentage of site space shifts from content to advertising.
It creates a risk that the visitor will find the site less appealing or click on fewer links because less content is being displayed.
Sites that take a more aggressive approach and use more than three ads per page may see ad performance deteriorate because site visitors see too many options.
- “Too busy” is a common criticism of sites that jam too much onto a page — including ads.
- In addition, too many ads will add to page weight and require more server calls, both of which will slow the page.
- These days, Google in particular is rewarding sites for fast-loading pages and punishing sites with slow pages.
- Eye-tracking studies show that the majority of site visitors click on links “above the fold,” meaning above the browser status bar. Putting more than three ads on a page requires placing them below the bar. It violates the viewability standard, reduces the click rate and results in a lower CPM or CPC depending on how it was sold.