The source – support.google.com
Starting March 1, 2022, Google AdSense will only show ads in recommended content blocks. The new format will be called Multiplex Ads.
Recommended Content Blocks was originally conceived as a feature that would offer visitors to a site's other pages. But it wasn't popular, so AdSense decided to make them ad-only.
Other changes:
- Minimum requirements will be eliminated.
- The Sites > Recommended Content page will be removed from the AdSense interface.
- Only the new ad format will remain in the recommended content block editor.
- The AdSense lab for recommended content will be disabled and marked as obsolete (relevant for those participating in beta testing).
