Glue

Google runs two related memorization systems on the same click logs. Navboost re-ranks the ten blue links by remembering which results people clicked for a query. Glue extends that logic to everything else on the page: knowledge panels, image packs, video carousels, People also ask, local packs, and featured snippets. Judge Mehta’s 2024 liability ruling treats Glue as the counterpart to Navboost for universal-search features, and Google’s VP of Search, Pandu Nayak, testified that Glue is just another name for Navboost that includes all of the other features on the page.

What Glue actually measures

Instead of counting clicks alone, Glue folds in hovers, scrolls, and swipes, then converts them into one common metric so a video carousel and a plain link can be compared. Over a rolling window of aggregated user data, it learns which feature best satisfies a query. Search a movie title and Glue may decide a video carousel belongs near the top; search a definition and it may promote a featured snippet.

Two practical takeaways. First, Glue is trained on aggregated behavior, so single-page tricks like forcing one click do not move it. Second, the “feature” that wins a query is often not a blue link at all, which is why a page can rank first organically and still lose most of the visibility to a panel or carousel sitting above it.