Why has Google devalued so much?

first our market is bad, growth stock don't do good in recession.

second, ComScore came out and told the world Google's ad-click rate has decreased so people want to get out of it because they believe Google will have trouble deliever this quarter.

when everyone is selling stock, the value goes down.

I hold my Google stock because I didn't believe stupid ComScore's BS data and I don't believe Google will be hurt that much by our current economy since online advertising is still a huge market, also with olympics coming up things shouldn't be bad.

I am glad I believed my instinct and hold my GOOG stocks, tomorrow i'll recover all my loses with some gain :)

Stocks like GOOG are valued based upon their future potential earnings. So small changes in projections lead to big swings in the stock price.

The opposite is also true. GOOG came out with good earnings today after the close. The stock is up $70 today in after hours trading.

All good things must come to an end and so also with the uptrend Google was experiencing in 2007. The stock is worth what buyers are willing to pay for it. It is all speculation on future value. The down trend it has seen since the end of 2007, matches the general market trend. I expect the bottom process the market is going through now is mostly over thus I would not be surprised if Google starts back up again as buyers start speculating again.

You are confusing price with value. The question should be: how did the price get so much above it's value. Or, maybe, what is the true value now and why is the market price so far above that?