Instant Search (often known as search as you type, type-ahead search, and auto-completion) is becoming increasingly popular in many Web applications. Such a system can find relevant answers as a user types in a keyword query character by character. The quick feedback can not only help the user formulate a query, but also help them find answers more easily. Such features are especially important for mobile users, since it is not easy to tap in keywords in such devices. On 9/08/2010, Google Instant was officially released on their blog, and which has been shown to save 2-5 seconds per Web search. Its success made many developers think about how to support this kind of information-search paradigm in their own applications. This blog is to give an overview of instant search.