[x] CHAPTER 1: SCALE FROM ZERO TO MILLIONS OF USERS
[x] CHAPTER 2: BACK-OF-THE-ENVELOPE ESTIMATION
[x] CHAPTER 3: A FRAMEWORK FOR SYSTEM DESIGN INTERVIEWS
[x] CHAPTER 4: DESIGN A RATE LIMITER
[x] CHAPTER 5: DESIGN CONSISTENT HASHING
[x] CHAPTER 6: DESIGN A KEY-VALUE STORE
[x] CHAPTER 7: DESIGN A UNIQUE ID GENERATOR IN DISTRIBUTED SYSTEMS
[x] CHAPTER 8: DESIGN A URL SHORTENER
[x] CHAPTER 9: DESIGN A WEB CRAWLER
[x] CHAPTER 10: DESIGN A NOTIFICATION SYSTEM
[x] CHAPTER 11: DESIGN A NEWS FEED SYSTEM
[x] CHAPTER 12: DESIGN A CHAT SYSTEM
[x] CHAPTER 13: DESIGN A SEARCH AUTOCOMPLETE SYSTEM
[x] CHAPTER 14: DESIGN YOUTUBE
[x] CHAPTER 15: DESIGN GOOGLE DRIVE
[x] CHAPTER 16: THE LEARNING CONTINUES