Google revealed major update at a special event on its 15th birthday, that update has been rolled out in past month and is live now. Algorithm Changes affected the search queries to give more correct answers to long questions. Hummingbird represents the revised way of indexing websites, which changes the algorithm named Caffeine, updated three years ago in 2010.
This update is targeted towards mobile/voice search based users. Most people will not notice the impacts for their search by algorithms changes. But users who make complex queries by voice search will get better information now after the update. Users who use smart phones, search long questions to get accurate answers by voice search. Update to algorithm is targeting more on websites ranking for better relevance by tracing into company's Knowledge Graph, as told by Amit Singhal, Google's senior VP of search team.
This is specially targeted towards long term based queries so the web masters and site owners, who are doing SEO for short term queries, need not worry about this update affecting them. But Websites which are getting high volume of visitors by searching long tail queries need to be concerned about necessary changes to their websites because it can be the major update for SEOs, web masters or website owners.