Your question is Design a Cold Start Ranker. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
You are building a recommendation feed for a consumer app. The system works well for active users and established content, but new users and newly created items have little or no interaction history, so ranking quality drops early in their lifecycle.
How would you handle the cold start problem in a recommendation or ranking system?