System design interview question
Design a Real-Time Activity Feed System like LinkedIn's Home Feed
Design a distributed system that powers a real-time activity feed for 500M users, where each user can see personalized posts from their 1000+ connections on average. The system must handle 50K write operations per second (new posts, comments, likes) and serve feed reads with <500ms latency to users distributed across 5 continents. Posts must be ranked by relevance and recency, and the feed must update within 2-3 seconds for followers of a given user. Consider handling 100 billion posts in the database, managing hot users with millions of followers, and supporting efficient pagination. The system must maintain eventual consistency while preventing duplicate entries and handling temporal anomalies across regions.
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