Add section on recommendation systems

[tonghuikang]

Personal introduction: I work in recommendation systems at Quora for almost a year now. I am currently not involved in ML interviews, but these are what I feel are good general questions to ask to evaluate expertise in recommendation systems.

Useful resources

• http://patrickhalina.com/posts/ml-systems-design-interview-guide/
• https://www.youtube.com/playlist?list=PLvOO0btloRntAi-VnV06M1Bu0X1xljUUP (but this is in Chinese)
• https://developers.google.com/machine-learning/recommendation/
• https://applyingml.com/papers/#recommendation
• Designing Machine Learning Systems book
• https://www.unofficialgoogledatascience.com/2021/04/why-model-calibration-matters-and-how.html

[chiphuyen]

These are interesting questions -- let me think more about them. In the meantime, would love to hear thoughts from everyone!