Google Instant was released today, for a certain subset of users only. Google announced in their blog post that Google Instant is a new means of "googling". Instant search means that you only have to type a few letters of your search query, and Google search will instantly show you search results (before you press the enter key). As you enter more letters, the search results will instantly update, without having to reload the page. This search system was developed using JavaScript in the front end, along with Google's highly developed and fast search system behind it all. Query times of 0.3 seconds are very significant when your search results are updating as every character is typed!
Please note: This post is a test for Google Instant. I went to google.com, typed in "testing" and one of the top suggestion results was "testing google instant". I'll test and see if this blog post appears in the results quickly.
