A new reader and a low-exposure post pose different problems. X’s code has separate routing, filtering and candidate-lift mechanisms for them.
A visibility label is only one input. Follow the rules, viewer context and caller decisions that determine where a post can appear.
Ranking is followed by selection, visibility checks, conversation deduplication and feed assembly. A high-scoring candidate still has several decisions ahead of it.
X’s prediction model turns reader history and candidate features into action estimates and time-valued outputs. Here is how those estimates reach the ranking formula.
Before filtering and ranking, X has to find candidates for a reader. Following, interaction history, retrieval services and cached posts offer different routes in.
X’s candidate filters check identity, history, access and budgets before this ranking stage. Their order explains more than a list of weights can.
Copy links, negative feedback, same-author discounts and age limits, read from the code with the switches and assumptions left in view.
