CEO, aQuantiveRank: 11Why he matters: Does Microsoft still matter? The Vista operating system was greeted with a yawn, and the Zune MP3 player hasn't fared much better. But things may get interesting now that McAndrews has sold digital ad firm aQuantive to Redmond for $6 billion and will come aboard to help Gates & Co. take on Google in the online-ad game.
At Microsoft, McAndrews will be armed with a new weapon: Riax, a cutting-edge system for tracking the effectiveness of ads on rich-media sites. It's a proprietary tool he developed at aQuantive -- and something Google can't yet match.
Meet 50 Who Matter winner Gina Bianchini. Her site, Ning, lets anyone be a social networking mogul. (more) 
