Adhesion Ads vs Anchor Ads: What Works for Gaming Traffic

If you run a web gaming site, you have probably encountered two terms that sound almost identical: adhesion ads and anchor ads. Both are sticky ad units that pin to the top or bottom of the mobile viewport. Both generate consistent impressions without requiring user interaction. And both are staples of mobile web monetization.

But they are not the same thing, and the distinction matters, especially for gaming traffic where the viewport behavior is fundamentally different from a typical content site.

Defining the Terms

Adhesion ads are a general ad format category: a 320×50 or 320×100 banner that remains fixed to the bottom (or top) of the viewport as the user scrolls. They are served through any ad network or header bidding setup. You control the size, position, refresh rate, and styling.

Anchor ads are Google's specific implementation of this concept. In AdSense they are part of Auto ads; in Ad Manager they are an out-of-page format in Google Publisher Tag. Google handles their behavior, including when they appear, how they are dismissed and how they interact with the page. You have limited control over their presentation beyond enabling or disabling them.

The technical distinction matters because gaming sites have a unique viewport characteristic: your players are not scrolling. They are interacting with a fixed game canvas. This changes how both formats perform.

Why Gaming Traffic Is Different

On a news article or blog post, the user scrolls continuously. A sticky bottom ad competes with the content flowing behind it, and there is a constant scroll-vs-ad tension. Viewability is high because the ad is always visible, but user attention to the ad is low because the user's focus is on the scrolling content.

On a gaming site, the game occupies a fixed area of the viewport. The player's eyes are locked on the game canvas. A sticky bottom ad sits below (or beside) that canvas in a region the player is not actively using. This creates a fundamentally different dynamic:

1. No scroll competition. The ad is not competing with moving content. It just exists in a persistent, peripheral position.
2. High viewability, moderate attention. The ad is technically in view for the entire session, but the player is focused on the game. This drives high viewability scores (which affect CPM) but lower CTR.
3. Fewer scroll taps, more control taps. On content sites, scroll momentum sometimes causes accidental taps on sticky ads. Games have less scrolling, but players tap constantly, so an ad sitting right next to on-screen controls invites accidental clicks. Accidental clicks risk invalid-traffic policy action and lower bids, so keep clear space between the ad and any control.

CPM Comparison

Sticky units sit in the high-impact display tier. Across the gaming sites we work with, a well-run adhesion unit typically earns $4–10 CPM in the US, compared with $2–6 for a standard in-page 300×250 or 728×90. Where a unit lands in that range depends mostly on how much demand competes for it:

Illustrative US ranges from our experience; your rates depend on geography, format and season. These are not measured results for your site.

The key difference is competition. A custom adhesion unit can run through header bidding, with multiple SSPs competing in real time alongside Google's demand. An AdSense anchor draws on AdSense's auction (Google Ads plus other buyers that bid through AdSense), so it is a single demand channel with no header bidding pressure from other SSPs. In Ad Manager, anchor slots are served by your own Ad Manager setup, so they can compete with the demand you run there, but you still give up control over sizing and behavior.

The 320×50 vs 320×100 Decision

This is the most common sizing question for mobile gaming adhesion units. The answer depends on your game's viewport usage.

When to Use 320×50 (Standard)

• Your game canvas uses 85%+ of the viewport height
• Game controls are positioned near the bottom of the screen
• You are concerned about the ad encroaching on gameplay area
• Your audience skews toward smaller phones (screen height under 700px)

The 320×50 unit is unobtrusive. It takes up approximately 7–8% of a standard mobile viewport. Players rarely complain about it, and it generates steady baseline revenue across every session.

When to Use 320×100 (Large)

• Your game canvas leaves at least 15% of viewport height unused
• Game controls are centered or positioned at the top
• You are optimizing for RPM and the extra real estate does not overlap gameplay
• Your audience has larger screens (modern phones with 800px+ viewport height)

The 320×100 unit usually earns a meaningfully higher CPM than the 320×50. That matters for a persistent unit that generates impressions throughout the entire session. But it occupies roughly 14–15% of the viewport, nearly double the footprint. If it overlaps game controls or reduces the playable area in a way players notice, you will see session duration drop.

The Test

Run a 14-day A/B test comparing the two sizes. Track:

1. CPM difference. Measure how large the premium actually is for your traffic.
2. Session duration. If the larger unit reduces average session duration by more than its CPM premium adds, it is not worth it.
3. Games per session. A more sensitive metric than session duration. If players are playing fewer rounds/levels per session, the larger ad is encroaching.
4. Player complaints. Monitor any feedback channels. The 320×100 unit is noticeable, and vocal players will tell you if it bothers them.

Implementation Best Practices for Gaming Sites

Position: Bottom, Not Top

Top-positioned adhesion units tend to underperform on gaming sites. The reason: most web games render the primary game canvas starting from the top of the viewport. A top adhesion unit pushes the game down, potentially cutting off the bottom of the canvas or requiring a resize. A bottom adhesion unit sits beneath the canvas without affecting its position.

Bottom positioning also avoids interfering with browser UI elements (address bar, tab bar) that occupy the top of the mobile viewport.

Lazy Load After Game Starts

Do not load the adhesion unit on initial page load. Wait until the game canvas has rendered and the player has started interacting. This achieves two things:

1. Faster initial page load. The ad request does not compete with game asset loading.
2. Better viewability timing. The ad loads when the player is already engaged, ensuring the first impression counts.

A 2–3 second delay after game start is usually sufficient. Some publishers wait until the first game action (first tap, first move) to trigger the adhesion load.

Refresh Rate: 30–60 Seconds

Adhesion units should refresh to serve new ads periodically, and only while the unit is actually in view. For gaming traffic:

• 30-second refresh is appropriate for fast-paced games where sessions are short. It maximizes impressions per session.
• 60-second refresh is better for longer-session games (card games, RPGs, strategy). It reduces ad fatigue and maintains CPM by not oversaturating.
• Never go below 30 seconds. Buyers discount inventory that refreshes too fast. Google Ad Manager requires you to declare refreshing inventory, with a 30-second minimum for time-based and event-triggered refresh (Ad Manager help).

Close Button Considerations

Some adhesion implementations include a close (dismiss) button. For gaming sites, this is a trade-off:

• With close button: Players who find the ad distracting can dismiss it. This improves UX but reduces total impressions, because some players will always close it.
• Without close button: Maximum impressions, but some players will find the persistent ad annoying. For gaming traffic, this is usually acceptable because the ad is in a non-competing viewport area.

Our recommendation: include a close button that is visible and usable from the start, and make the unit reappear on the next game/level start. This gives players control without permanently losing the ad slot.

Z-Index and Overlap Prevention

This is a technical detail that causes real revenue problems when ignored. Your adhesion ad must have a z-index that keeps it above the page background but below any game UI overlays (pause menus, settings panels, reward popups).

If the adhesion unit renders on top of a game popup, players cannot interact with the popup, and they will blame the ad. If a game overlay covers the adhesion unit, the ad keeps serving and refreshing while nobody can see it. That wastes advertisers' money, can inflate your viewability numbers, and ads obscured by page content are the kind of thing exchange policies prohibit. Pause refresh while an overlay covers the unit.

Set the adhesion container's z-index to a value between your base page layer and your game's overlay layer. Test every overlay state to confirm no conflicts.

Google Anchor Ads: When They Still Make Sense

Even if they earn less than a header-bid adhesion unit, Google anchor ads have a valid use case: simplicity. If you are running a small gaming site with limited ad ops resources, enabling anchor ads in AdSense Auto ads takes a few clicks. No custom positioning, no z-index debugging, no refresh rate configuration. Google handles it all.

They also make sense as a fallback. If your header bidding adhesion unit fails to fill (no bids above your floor), the slot can fall back to Google AdX/AdSense demand in the same Ad Manager slot, catching impressions that would otherwise go unfilled.

What to Do Next

For gaming traffic, a header-bid adhesion unit usually earns more than a Google anchor ad, because more demand competes for it. The fixed-viewport nature of games suits the format well: little scroll competition, consistent viewability and clean separation between the ad and the gameplay area. Start with 320×50 at the bottom of the viewport, test 320×100 if your layout allows it, refresh only while in view and no faster than every 30 seconds, include a close button, and get your z-index right.

The adhesion unit will never be your highest-CPM format, but it is one of the most consistent. For how it fits alongside other formats, read choosing the right ad format for your game genre, or see publisher results.