Fear is a great motivator. The fact that Microsoft, the Goliath of the technology industry, has been spooked into another attempt to buy Yahoo is testament to Google's speed and aggression in dominating key chunks of the online world.

Google has long led the lucrative area of search-related advertising, on its own and third-party sites. Now it is pushing for similar dominance in serving display adverts. Its acquisition of DoubleClick was probably the last straw. It even goaded Microsoft (of all companies) to challenge the antitrust implications.