What factors are leading to the continual decline of Google's stock since it's 2010 high of 625+ a share?

About a month ago, Google reached 627.00 per share .. Since then the stock has steadily declined now down to a whopping 577.81 a share, with no sign of promise. I have tried to research reasons for the steady decline over the past few weeks, but have come up empty handed. The only reason I could feel has an effect on the stock would maybe be the investors disappointment with the introduction of the Nexus One phone