Why do website pages fail to load or display content with ad blockers?

Key findings

• Primary cause: Ad blockers, particularly extensions like uBlock Origin, frequently prevent website content from loading.
• Script blocking: Marketing automation scripts, such as those from Marketo, are a common target for ad blockers, often causing forms to fail.
• Inadvertent blocking: Essential website functionalities, like contact forms, can be blocked if their underlying JavaScript is flagged as an ad or tracker.
• Browser variation: Website loading issues with ad blockers can vary across different browsers due to their unique handling of extensions and script execution.

Key considerations

• User experience: Websites that fail to load with ad blockers provide a poor user experience, potentially driving visitors away and increasing bounce rates.
• Content access: Crucial content or interactive elements may become inaccessible to users with active ad blockers, hindering engagement and information delivery.
• Development practices: Developers must consider how ad blockers might interact with website code, especially third-party scripts, to ensure robust functionality.
• Alternative access: Providing alternative ways to access content, such as direct links to downloadable files, can bypass blocked forms and ensure content accessibility.

Key opinions

• Ubiquitous problem: Many marketers confirm experiencing similar page loading issues when ad blockers are active, indicating it's a widespread challenge.
• Marketo JS: Marketo forms and their associated JavaScript are frequently identified as elements blocked by ad blockers.
• Privacy defaults: Ad blocker privacy settings often categorize legitimate marketing scripts, like those for forms, as blockable content, even if they aren't directly ads.
• Developer responsibility: Websites should implement robust loading mechanisms or provide alternative content access when forms are blocked, rather than just failing to load.

Key considerations

• Lost conversions: If forms or calls to action are blocked, potential leads or conversions are lost, directly impacting marketing ROI.
• Data integrity: Analytics scripts being blocked can lead to incomplete or inaccurate website performance data, making it difficult to assess campaign effectiveness.
• User friction: Forcing users to disable ad blockers creates friction and can lead to abandonment, eroding trust and discouraging future visits.
• Content accessibility: Marketers need to ensure that valuable content remains accessible even if gated forms are blocked, perhaps by offering direct downloads or alternative access methods, similar to ensuring emails bypass email blacklists.

Key opinions

• Ajax complexity: Websites that rely on complex AJAX calls to load forms or content are particularly vulnerable to ad blocker interference.
• Validation gaps: Some web forms have lax validation for user inputs like phone numbers, which can lead to privacy concerns even without ad blockers.
• Content access philosophy: There is an ongoing debate on the ethics of blocking content access to users who employ ad blockers versus providing direct content links.
• Data collection practices: Experts express concern about the extent to which third parties can track user interactions and collect data, even if it’s anonymized.

Key considerations

• Filtering mechanisms: Understanding how ad blockers filter and block resources, much like how email filters operate, is crucial for web development and content delivery.
• User autonomy: Users increasingly expect control over their browsing experience, including the ability to block unwanted content and trackers.
• Revenue vs. UX: Websites must weigh their advertising revenue models against the potential negative user experience caused by aggressive ad blocker detection and content blocking.
• Performance optimization: Optimizing website performance, particularly by reducing reliance on numerous external scripts, can sometimes mitigate the impact of ad blockers.

Key findings

• Script detection: Ad blockers often detect advertising or tracking scripts by their URLs, filenames, or specific code patterns, leading to their blocking.
• Resource blocking: They can block various web resources, including images, scripts, stylesheets, and even fonts, if they match predefined filtering rules.
• Error logging: Browser developer tools typically log a ERR_BLOCKED_BY_CLIENT message when a resource is blocked by an ad blocker or other browser extension.
• Analytics impact: Analytics and social network scripts are frequently blocked by ad blockers, leading to incomplete or unreliable data for website owners.

Key considerations

• Third-party scripts: Websites should carefully evaluate the necessity and impact of third-party scripts, as they are often primary targets for blocking.
• Graceful degradation: Implement designs that allow websites to function adequately, even if certain non-essential elements are blocked, ensuring a basic level of usability.
• Whitelisting instructions: Clearly inform users if ad blockers are interfering with site functionality and provide straightforward instructions for whitelisting the site, if appropriate.
• Server-side rendering: Where feasible, consider server-side rendering for critical content to bypass client-side script blocking and ensure content display.