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Learn why platforms struggle with new users who have no history, and how they solve it
Part of How Netflix, Spotify, TikTok Know You
Educational content slides
You download TikTok. Open it. First hour feels chaotic:
Cooking video (watch 2 seconds, skip)
Prank video (watch 3 seconds, skip)
Anime edit (watch 47 seconds, like, comment)
Dance video (watch 8 seconds, skip)
Anime meme (watch full video, share)
Within 20 minutes: TikTok knows you better than Instagram after 2 years
The secret: Aggressive exploration with rapid feedback. Each skip/watch/like is a data point. Short videos = fast learning.
This solves the cold start problem in real-time.
Test your understanding with this quiz.
Why does Spotify ask new users to pick 3 favorite artists during signup?
Complete this exercise and get AI-powered feedback.
Cold start is every recommendation system's first challenge. How you solve it determines whether users stay or leave.
Think about: How to gather data quickly without annoying users, when to explore vs exploit, how to balance learning and satisfaction.
This reveals: The fundamental tension between learning and serving in recommendation systems.