Top Ad Formats for Publishers in 2025

In 2025, digital publishers are increasingly using sticky ads, interstitial ads, side rail ads, and rewarded ads on their websites and apps because these formats have been shown to improve key metrics such as CTR and viewability, while also boosting user engagement and ad revenue.

Introduction

2025 has marked an important year for ad formats in the editorial media publishing industry. Publishers are navigating both a decrease in average eCPMs and evolving user behavior, alongside the continued dominance of mobile activity.

There is growing user demand for fast-loading, non-intrusive page experiences alongside mounting pressure on advertising revenue streams, meaning publishers must carefully refine their approach to ad formats and optimization techniques.

In this article, we will dive into key ad formats publishers should focus on to achieve sustainable growth and improve overall performance.

What Are the Key Ad Formats in 2025?

Digital ad formats in 2025 focus on high viewability, a non-intrusive page layout, and maximal monetization potential.

Among the top ad formats this year, four stand out for their ability to blend performance with user satisfaction: sticky ads, interstitial ads, side rail ads, and rewarded ads.

Sticky Ads

What are sticky ads?

A sticky ad is an ad unit that remains visible in overlay on the page as the user scrolls through content.  Sticky ads are among the most preferred formats by users. 

When implemented properly, sticky ads significantly boost revenue because they deliver at least one additional ad impression per pageview. But more frequently, it is more than just one. This is thanks to the fact that they remain visible on-screen while users read content, and ads may rotate automatically.

For example, Gizmodo saw a 43%+ increase in revenue after Opti Digital implemented sticky ads on their mobile site.

Sticky Ads Benefits

Sticky ads’ high viewability and extended time in view allow them to rotate effectively.

This leads to higher engagement (CTR) and post-click conversions, driving greater demand for these placements, higher fill rates, eCPMs, and overall monetization.

Sticky Ads Best Practices

Sticky ads should be positioned seapararely from the main content to maintain a seamless user experience,

Flexible placement with common sizes like 320×100 or smaller (mobile leaderboards) and 728×90 (desktop leaderboard) helps publishers achieve this balance.

Ad Manager Hub by Opti Digital allows publishers to further customize sticky ads, including:

• Choice of position (top, bottom, right, left).
• Trigger for the sticky ad (on page load or after scrolling a certain distance).
• Placement of the close button (left, right, out or in the ad space, or none).
• Exclusion of specific pages from being displayed as sticky ads.

Interstitial Ads

What are interstitial ads?

Interstitial ads are ad formats that take over the site’s interface, appearing as full-screen ads on mobile devices or as floating overlays on desktop pages, designed to respect user experience by being easy to close, while offering publishers high performing opportunities.

Interstitial ads are typically triggered by user actions such as clicking on specific URLs within the site. Google Ad Manager allows publishers to configure several additional triggers for these ads.

Beyond link clicks, interstitials can also be displayed when a user returns to a previously hidden tab or window (“unhide window/tab”), or when they interact with the browser’s navigation bar (on desktop).

Interstitial Ads Benefits

In 2025, interstitial ads are particularly vital in a mobile-first strategy as, according to SQ Mag, interstitials generate 3.5x higher engagement than banner ads, particularly within apps, translating into a great monetization opportunity for publishers.

This ad format is especially relevant, as our study done earlier this year revealed that a significant 68.37% of online users access their favorite information sources via mobile, highlighting the importance of mobile-first strategies.

Interstitial Ads Best Practices

Interstitial ads should be integrated thoughtfully within the natural flow of the app or website to ensure they complement user engagement rather than disrupt it. A clear exit option should always be provided.

Placement at natural transition points, such as between sections or pages, helps maintain a positive user experience and reduces accidental clicks. In gaming apps, it is better located between game levels. 

Frequency capping should also be implemented, limiting the number of ads shown to each user within a set timeframe, typically once per hour per subdomain, to prevent ad fatigue.

Side Rail Ads

What are Side Rail Ads?

A side rail ad is an ad format that is fixed to the left or/and right sides of content in widescreen desktop layouts, remaining visible as users scroll through content. Screens must have a minimum resolution of 1200×650 to ensure proper layout, meaning that they are almost exclusively a desktop ad format. 

These ads utilize the wider screen real estate effectively without interfering with the main content, contributing to maximizing the ad revenue while offering a healthy UX.  

Benefits of Side Rails

These adsincrease monetization and viewability of ads by taking advantage of unused side space. 

Side rail ads are especially useful when a site is narrow on desktop and leaves significant side space. One of our publishing partners with such a design saw a 70% uplift in ad revenue with side-rail formats as they could deliver side rail ads on laptop screens as well.

Side Rail Best Practices

These ads support 120×600 and 180×500 creative sizes and are designed to display only on screens with a minimum resolution of 1200×650. 

Rewarded Ads

What are Rewarded Ads?

Rewarded ads are ad formats designed to create engagement by offering users a tangible incentive in exchange for viewing an ad. The user sees a preview of the content and must view an ad to continue reading.

Rewarded Ads Benefits

Rewarded ads deliver high viewability because users actively choose to open and view  them, ensuring that impressions are seen and completed. This opt-in model also drives strong engagement signals, as interactions are voluntary and tied to meaningful rewards, which enhances user satisfaction and retention.

Also, these clicks to open and view ads are interpreted as engagement signals taken in consideration for SEO so they benefit the website’s ranking in Google SERPs.

These ads can boost revenue performance significantly, delivering  eCPMs ranging from €5 to €30 in the UK and Western Europe, CTR between 10–15%, and consequently generating an increase of ad revenue per page between 10–25%.

Rewarded Ads Best Practices

Rewarded ads are most effective when placed within premium or high-value content that users care about. By partially restricting access to content or features, users are given an incentive to engage with the ad in order to unlock the full experience.

This approach encourages opt-in participation while maintaining a positive user experience, as the reward feels meaningful and directly tied to content the user values.

With Opti Digital, you have full control over how the locked section is presented to users. The preferred option is the blur effect, where the content remains visible but unreadable, preserving layout while signaling that more lies ahead.

Alternatively, the hide effect removes the section entirely until it is unlocked. Both can be customized with adjustable blur intensity, gradient fades, exclusion rules, and a personalized “read more” button with your own label and style.

Publishers can even display a progress message showing how much of the article remains locked, ensuring transparency and reinforcing the value of the reward.

Which Ad Format Performs Best in 2025?

Choosing the best ad format depends largely on your audience, content layout, and monetization goals. Each of the formats brings unique strengths.

These data points can vary significantly depending on the industry, vertical, and medium, so they should be used only as a benchmark or reference point for comparison.

Test these ad formats alongside your existing ads with a simple integration of our lightweight JS tag. Contact our team to get started and see how Opti Digital can boost your revenue!

Bonus – Carousel Ads

Beyond the above listed ad formats, it is important to keep innovating and experimenting in the ad frame itself. Our team developed Demand Hub, which offers a unique ad experience that blends advanced technology and seamless user experience in traditional IAB ad placements

Demand Hub features a dynamic carousel that rotates deals and campaigns  within one placement. Mimicking social media stories and triggering rotation when in view, it captures user attention, boosts viewability and click-through rates for brands to achieve their goals and for publishers to maximise their revenues.

Supporting all common IAB ad sizes on desktop and mobile, Demand Hub is available through Prebid. Trusted by over 10,000 media partners and delivers an average revenue lift from +7% to +10% in RPM.

Key Takeaways

To maximize ad revenue in 2025, publishers must balance monetization with user experience, across both mobile and desktop, for sustainable long-term growth.

For publishers seeking to implement these strategies seamlessly, Opti Digital offers technology, testing capabilities, and layout optimization tools to maximize monetization potential and a better UX. Make sure to get in touch if you would like more information!

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