The new engine, called Hummingbird, is the first change to Google’s core algorithm since the launch of Caffeine in 2010. Hummingbird, said Amit Singhal, Google senior vice president and one of its earliest employees, affects 90 percent of searches with Google worldwide.

Singhal was careful to note that while page ranking and indexing are bound together in a search engine, Caffeine focused more on the ranking side of the algorithm. Hummingbird is more about indexing.

Read: Google Search now powered by a Hummingbird | Internet & Media – CNET News.