What are invisible display ads?
Invisible display ads (IDAs) are online advertising units that register as delivered by a typical ad server, but are not viewable by a site visitor. As a result, advertisers are billed for ads that did not run.
Why do invisible display ads occur?
Most invisible display ads occur on sites participating in an online advertising network. Sites use this technique to maximize revenue. To date, they have been traditionally difficult for the online advertising networks to identify and police. They typically involve offending sites changing only one line of HTML in order to dramatically increase the number of ads sold.
How do unscrupulous sites implement invisible display ads?
A simple line of HTML code can allow an IDA to appear. There are a variety of IDA /impression fraud approaches. Essentially, ads are served within an iframe, much like a typical display ad, but not viewable. This allows multiple ads to be served in the same position or for ads from other sites to be run while visiting another site. There are few barriers of entry and almost no technical difficulty for a site to implement.
What are the most common ways offending sites use to implement invisible display ads?
There are three typical "impression fraud" techniques used:
1.) Piggy-back iframes - iframes with no height or width
a. Sites add multiple iframes below established ad positions.
b. While the site visitor only sees one ad in the appropriate position, additional ads are served below it, just not visible.
2.) Size-less iframes - large iframes that can load numerous sites and ads
a. Technique allows an out-of-plan site to run advertising, albeit invisible, from approved sites
b. Hidden iframe loads actual sites and advertising. Ads appear delivered, but not viewable by the viewer.
3.) Display blocking iframes - correctly sized iframes that don't show visible ad
a. Ads appear to serve in appropriate position, but are set not be viewed
b. Difficult to detect, given that the ads run in the correct position.
What are some IDA protection strategies?
Look beyond delivery to verify that your campaign isn't being billed for invisible display ads. Unfortunately, looking at each site on your media buy on a regular basis is untenable to all but the smallest campaigns. Advertising programs need to measure delivery and subsequently validate context on an automated real-time basis. Among the devices used by DoubleVerify and other providers, are pixels embedded in your advertising to verify delivery and, in parallel, use of a network of crawlers to ensure that your ad did appear and that the site was compliant.