Google updates its app for iOS to bring the useful 'OK Google' voice prompt and have it always on and ready to respond to your voice. Aside from that, it helps your searches further by giving you contextual information. For example, you're reading an article on a celebrity. You can say, "OK Google, where is he or she born?" And it will answer you based on the article you're reading. It also has more detailed local search results now to make it easier for you to find what you need. 

Source: Lifehacker | Download: Apple App Store (Free)