Revenue growth is the key component for investing in growth companies. Institutions will be taking a close look at this one. I don't think GOOG will experience a huge sell off in this case. In fact, GOOG is actually up $4+ while I'm writing this---now $5. We'll see tomorrow how the large institutions interpret this slow down in revenue growth.
Just a matter of selling more, but charging less. Works for the "Peoples Republic of Capitalism", doesn't it? If the whole economy would be able to do it, we could compete with international markets. But let's not confuse sale of goods, with sale of services.