At a press conference announcing the change, Google explained that the new algorithm is smarter, able to understand complex queries and return more relevant answers. They are preparing for a future of phone concierges, where you ask your phone for information and it talks back to you, understanding the meaning behind your questions and giving you semantically relevant answers.
According to the NY Times:
“The company made the changes because Google users are asking increasingly long and complex questions and are searching Google more often on mobile phones with voice search.” More from this article by Marcela De Vivo>>>