In 2007 more humans lived in cities than outside them for the first time. It was a transition 5,000 years in the making. The internet has been quicker to reach the halfway mark. Over 50% of the planet’s population is now online, a mere quarter of a century after the web first took off among tech-savvy types in the West. The second half of the internet revolution has begun. As our briefing describes, it is changing how society works—and also creating a new business puzzle.