For the first time in their collective history, Google passed Microsoft in market cap in early Monday trading, making it the world’s second most valuable tech company behind Apple. With a slight drop in share price by Microsoft, and a commensurate gain by Google, the search giant approached $249 billion while the Windows-maker dipped below $248 billion. A billion here, a billion there, and pretty soon we’re talking about real money. If google passes $250 billion, it will eclipse WalMart – as things currently stand – to become the number three largest US company behind Apple and Exxon Mobile. [Source Mashable]