As reported in April Apple was already close to over take Microsoft in terms of Market Cap. At the close of the market yesterday it has happened. Apple has a Market Cap of $222 billion and Microsoft has a Market Cap of 219 billion.
This event has something symbolic as Microsoft is struggling to innovate and compete in the new markets Apple is shaping. Just look at smartphones and now the tablet market.
Microsoft is also in a restructuring mode in this area. Steve Ballmer knows that things have to change to succeed in the future. Windows on PCs will not be enough going forward.