Are Expandable Ads Right for You? (Benefits + Security Concerns)

Expandable ads expands on users’ screens when users interact with them. These ads offer high CTR and brand awareness, but not without security issues.

Expandable ads promise high CTR, better viewability and user engagement by showing larger-sized ads containing image, text, video, and rich media content. According to a study, expandable ads encourage 0.16% users to click on ads in comparison to banner ads where this number is 0.10%. And we all know that advertisers have an affinity for high viewability inventory. But is the promise of these ads worth it?

Yes, there is high CTR, however, there is always a concern for bad user experience and security issues. So, let’s dive into the topic and hope by the end you would know whether to go for expandable ads or not.

What Are Expandable Ads

Expandable ads are rich media ads that expand from their displayed ad size to outside the iFrame to other bigger sizes when users interact with them. Due to this interaction, these ads create better interaction possibilities and can deliver more information to interested users. For instance, expandable ads can show video clips of a game, information about upcoming sale or trailer of a movie that might interest users.

In display advertising, click-to-expand ads can expand to sizes as large size as 728×270 pixels. Generally, these click-to-expand ads look like any other ads on a webpage, however, as soon as users click on these ads, they expand on the screen (might take up to 70% to 100% screen) giving users all kinds of minute details they would want to know about the product or the brand.

With expandable ads, publishers can make good money out of cost-per-click (CPC) or cost-per-impression (CPM) campaigns. Keep in mind that you’ll generate earnings from CPC expandable ads when a user clicks on ad to visit the advertiser’s landing page, and not when a user simply clicks to expand the ad.

Popular expandable banner sizes

These ads are designed in two sizes for two states. A small size called ‘invitation state’ and a large one called ‘expanded state’.

Invitation state unit sizes: 120×600, 160×600, 200×200, 250×250, 300×250, 300×600, 336×280, 468×60, and 728×90

Expanded state unit sizes: 240×600, 320×600, 400×200, 500×250, 600×250, 672×280, 468×180, and 728×270; corresponding with the previous invitation state unit sizes.

The Benefits

In totality, expandable ads benefit advertisers by giving them what they aspire for—interested audience. And happy advertisers mean better revenue for publishers.

Frequently Asked Questions by Publishers

The Matter of Security

Ads that expand on user’s screen can be abused as an entry point for hacks. Randy Westergren, a Delaware-based security researcher found, iFrame busters used to expand ads make your site vulnerable to attacks.

Let’s start from the starts. Ad units are given a fixed ‘frame’ or iFrame on webpages to display creatives. Then we have two types of iFrame —friendly iFrame and non-friendly iFrame. The former one has the same domain as the hosted webpage domain. This iFrame allows the content of the frame to ‘break out’ and take up more than allocated space. Next, non-friendly iFrame has a different domain than the hosted webpage and do not allow the expansion beyond the allocated space. Hence makes things tricky for the expandable ads to work. This is because, ad code has different domain than the hosted domain. To tackle this problem, iFrame buster comes into the picture.

An iFrame buster code is added to allow expansion of ads beyond their frame limit. And according to Randy Westergren, iFrame buster can be exploited by an attacker in a DOM-based cross-site scripting (XSS) attack. XSS or cross-site scripting is a client-site code injection attack. Meaning, during the expansion of ads, iFrame buster provides a window for attackers to push their malicious code using XSS.

Hence, publishers need to be cautious about similar attacks while implementing expandable ads.