Hummingbird - a completely new engine.
Google revealed the existence and prior rollout of a new algorithm named “Hummingbird,” its biggest update since 2001. Despite its understated introduction, this update is likely Google’s most dramatic change in over a decade—Hummingbird is a completely new engine. Having more impact on long-tail searches, the new algorithm focuses heavily on improving conversational search and understanding user intent. Hummingbird will still include many old factors (such as PageRank) but will be more effective at including newer items like schema.org semantic markup.