How does Google sell ad space and rank webpages? How does Netflix recommend movies and Amazon rank products? How can you influence people on Facebook and Twitter and can you really reach anyone in six steps? Why doesn't the Internet collapse under congestion and does it have an Achilles' heel? Why are you charged per gigabyte for mobile data and how can Skype and BitTorrent be free? How are cloud services so scalable and why is WiFi slower at hotspots than at home? Driven by twenty real-world questions about our networked lives, this book explores the technology behind the multi-trillion dollar Internet and wireless industries. Providing easily understandable answers for the casually curious, alongside detailed explanations for those looking for in-depth discussion, this thought-provoking book is essential reading for students in engineering, science and economics, for network industry professionals and anyone curious about how technological and social networks really work.