Google published new research on how to improve Google Discover with a more accurate system for identifying and removing stale content. The new system, Supersession-Decay Filtering (SDF), is already in use by Google and is affecting what content is shown to users.

Supersession-Decay Filtering (SDF) Is Already In Use

The word “supersession” is derived from the word “supersede” and identifying when newer content has superseded older content is one of the two things this system does. The word “decay” relates to the other thing the system does, which is to predict when content usefulness is lost through relevance decay.

What may be shocking to the publishing and SEO community is that this system has been in use for two years. That means publishers, site owners, and SEOs need to catch up.…