What is the relevance of 'viewability' metrics when optimizing AdSense ad placements?

Viewability metrics are highly relevant when optimizing AdSense ad placements because they directly measure the percentage of ads that are actually seen by users. An ad impression is only considered viewable if at least 50% of the ad's pixels are visible on the screen for at least one second (for display ads) or two seconds (for video ads). Higher viewability rates mean that more users are actually seeing the ads, which increases the likelihood of clicks and conversions, leading to higher EPM and overall AdSense revenue. When optimizing ad placements, publishers should focus on placing ads in locations where they are most likely to be viewable, such as above the fold, within the main content area, or in sticky positions that remain visible as the user scrolls. Monitoring viewability metrics in AdSense reports or Google Analytics allows publishers to identify underperforming ad placements and make adjustments to improve viewability and maximize revenue. Low viewability rates can indicate that ads are being placed in locations that are not easily seen by users, such as below the fold or in areas with low engagement.