RETOOLED SEARCH ENGINE: Google has completed the most dramatic overhaul of its influential search engine in three years with an update called "Hummingbird." The new formula changes the way that the Internet's most popular search engine analyzes about 90 percent of the requests that it gets.
QUIET CHANGE: The different approach to search gradually rolled out during the past month. Google Inc. waited until Thursday to reveal the existence of the new formula at event held in the Menlo Park, Calif., garage where the company started 15 years ago.
POTENTIAL FALLOUT: The renovations could have ripple effects on the flow of online traffic and ad spending.