How the ranker grades like sources
Each like the ranker reads carries a source-quality grade based on the liking account's recent activity. The grade has three inputs:
- Recent app-open recency — when did the account last open TikTok. Same-session likes are weighted highest; same-day likes are weighted moderately; >7-day likes are weighted near zero
- Scroll-context — was the like issued while the user was scrolling the FYP, or as a direct-link visit. FYP-scroll likes are weighted higher because they represent the user choosing to like inside the recommendation flow
- Account-health — was the liking account's own content recently distributed and engaged with. Accounts the ranker treats as quality-creators give higher-grade likes to others
