You pick up your iPhone while waiting in line at a coffee shop. You Google a not-so-famous actor and get linked to a Wikipedia entry listing his recent movies and popular YouTube clips. You check out user reviews on IMDb and pick one, download that movie on BitTorrent or stream it in Netflix. But for some reason the WiFi logo on your phone is gone and you're on 3G. Video quality starts to degrade a little, but you don't know whether it's the video server getting crowded in the cloud or the Internet is congested somewhere. In any case, it costs you $10 per gigabyte, and you decide to stop watching the movie, and instead multitask between sending tweets and calling your friend on Skype, while songs stream from iCloud to your phone. You're happy with the call quality, but get a little irritated when you see that you have no new followers on Twitter.

You've got a typical networked life, an online networked life.

And you might wonder how all these technologies “kind of” work, and why sometimes they don't. Just flip through the table of contents of this book. It's a mixture: some of these questions have well-defined formulations and clear answers while for others there is still a significant gap between the theoretical models and actual practice; a few don't even have widely accepted problem statements. This book is about formulating and answering these 20 questions.