The move by Microsoft to acquire Yahoo has repeatedly been referred to as a bid for controlling web traffic versus Google. While clearly the combined entity would aggregate a far larger audience than MSN and Yahoo do individually this is actually a battle for something far larger. It's the battle for control of the advertising operating system.
Microsoft was built on a simple yet powerful premise. Focus on controlling, then scaling standards. While the aggregate audience on the web long ago reached the tipping point of a mass audience, the real scale will come from controlling the way the web itself is monetized. Microsoft understands this viscerally. So does Google. Its still very early in this battle. Regardless of your pov it will be fun to watch.,