Often abbreviated ATF. Opposite of below the fold, or BTF.
Though this adjective can be used to describe any element of a Web page, it is most commonly used to describe the position of an ad unit. Specifically, ad units placed above the fold are generally considered to be more valuable, since there is a higher likelihood that they will be seen by visitors.
Conversely, below the fold is used to describe the section of a Web page that is not immediately viewable by a user on a normal page load, but can be seen by scrolling down the page. This is generally a binary distinction; each element of a Web page, including ads, can be described as either above the fold or below the fold. Ads placed below the fold require the user to scroll down in order to see, so those are generally less appealing to advertisers (and are priced at a lower rate than otherwise similar above the fold units).
Below is a visual example; the black horizontal line represents the “fold” that segments the Web page. The ad boxed in a green line would be considered to be above the fold, while the ad boxed in red is below the fold:
There are a number of instances where the location of an ad unit can be important to an ad proposal, AdSense monetization, and even SEO strategy.
If you’re selling inventory directly to advertisers, odds are that they will ask you to specify the location of the line items you are proposing. This can usually be accomplished by simply including the relevant qualified in front of the ad unit. For example, the image above contains the following ads:
All else being equal, an above-the-fold ad impression is worth more than a below-the-fold ad impression. The difference between the value of these two can be significant; it isn’t uncommon for an ATF rectangle to generate revenue per thousand impressions (RPM) that is 2x to 5x higher than a similar ad unit positioned below the fold.
This is because above-the-fold ads will have a 100% “view rate,” meaning that every visitor who loads the page will see the ad. Below-the-fold ads are only seen by a portion of visitors to a page, since some don’t scroll down through the page.
Any sites that utilize AdSense as a way to fill display ad inventory is likely well aware of the difference in the value of ATF vs. BTF placements. AdSense serves most of its ads on a cost per click (CPC) basis, meaning that publishers only earn revenue when the ads shown are clicked. Ad units located above the fold will generally earn considerably more than otherwise comparable BTF units.
When designing a site, it’s worth considering where your ads will appear–especially if you plan to monetize primarily through display advertising. Generally, including two ad units above the fold is a good strategy; this will ensure that you have plenty of high value real estate to offer to interested advertisers.
This is relevant for sites that sell directly to advertisers as well as those that will monetize primarily through ad networks.
If you’re selling ads directly to advertisers, it’s important to keep in mind that the difference between ATF and BTF units includes significantly different performance metrics. Specifically, the click rates between the two will be very different. In most cases, the relative prices (assuming a CPM-based pricing strategy) should reflect this delta. In other words, most advertisers will expect that BTF placements are heavily discounted from above-the-fold ad units.
Keep in mind that many advertisers who pay on a CPM basis will measure the success of a campaign by calculating the effective cost per click (CPC) or cost per action (CPA). If ATF and BTF ad units have similar pricing, the BTF placements will likely have poor CPC and CPA metrics. That often leads to the advertiser optimizing out of that line item, which forces you to reallocate spend if you don’t want to lose revenue.
Given the high value of above-the-fold ad inventory relative to below-the-fold placements, it may be tempting to stuff the top of a Web page with ad units. But there are a couple reasons why this approach is likely to backfire: