Summary Box: Google’s 4Q letdown deflates stock

MISSING THE MARK: Google’s fourth-quarter earnings and revenue both came in well below analyst projections. It was a harsh comedown, given that the forecasts had called for the most prosperous quarter in the company’s13-year history.

THE BIG SURPRISE: The Internet search leader collected less money per click on its online ads. That came as a shock because a surge in online holiday shopping in the U.S. was supposed to increase the demand for Internet ads and enable Google Inc. to charge more for the marketing messages.

INVESTOR REACTION: Google shares plunged 9 percent in Thursday’s extended trading.