Everybody knows that John Murphy's all-time favourite tool is the relative strength chart. Intermarket analysis being his main area of expertise, it's understandable. And even if one can easily fall prey to overusing and overanalysing them, relative strength charts (or ratio charts) can be very useful. Shown above is simply the daily chart of (GOOG divided by SPY) and what it shows is that even though GOOG is making new all-time highs in absolute terms, it is still trading below its all-time high on a relative basis. Therefore (and you know where this is going), it still has room to go.
Granted I do own a few shares of Google and I am thus a prime candidate for the very common "cheerleader bias" where one only looks for facts supporting one's theories. I would be worried about it if GOOG were in a free fall, which is not the case (fingers crossed).