Asked about Matching people to items
How would you design a recommender system?
An answer that works
Two stages: cheap candidate generation narrowing millions to hundreds, then expensive ranking of those. Combine collaborative and content signals, handle cold start with content features and popularity, and include deliberate exploration.
Reading an answer is not being able to give one. The section that teaches this is Matching people to items, 5 hours of Recommendation systems.
Learn this properlyAlso asked about Recommendation systems