The briefing

What changed in search arbitrage, why it matters, and one thing to learn, once a week.

• Top stories rewritten in plain English, with why they matter.
• Fraud watch: the week in click fraud and invalid traffic.
• Market movers and new deals.
• One term to learn and a quiz question.
• Optional breaking alerts for feed and policy changes, fraud incidents, deals, earnings and big stock moves (never more than a few a day).