Google (GOOG) has given its core search algorithm its biggest update since 2010. The update, known as Hummingbird, is meant to provide better site rankings for complex queries, in part by leveraging Google's Knowledge Graph database.
A Google engineer says the growth of voice-based mobile searches is leading to more complex queries, which in turn helped drive the update.
Google is also updating Knowledge Graph to give users the ability to filter and compare items, and overhauling its increasingly pivotal mobile search pages. The pages now have a more streamlined, touch-friendly design, and include Google Now-like cards.
Meanwhile, Google's iOS search app (along with Chrome, crucial to lowering traffic acquisition payments to Apple) has been updated to include Google Now notifications (they've been around for a while on Android).
Also: The Android Gmail app has been updated to feature a card-like UI; Google now supports hashtag searches (but only for Google+); DoubleClick's display ad campaign software tools have been revamped; and (in an effort to improve quality) YouTube's comment system now requires a Google+ ID.
TechCrunch argues the last product update will give Google+ a much-needed user engagement boost.