main changes on the ranker: - freshness - now sees how old each post is - dwell time - it sees how long you looked - location - a hashed IP signal feeds into your profile - new users - get routed to a dedicated ranker cluster - position anchoring - your most recent action always sits in the same spot, so recent activity counts consistently - language - each post's language is an input - media/video - video length influences scoring - mutual-follow overlap - how much your social graph overlaps with the author's - brand safety - every post gets a low/medium/high risk verdict - friends-in-thread - knows if people you follow already replied - served history - the system remembers what it already showed you - ads in safe gaps - ads avoid sitting next to sensitive content - continuous training loop - your impressions feed straight back into retraining