Google has been experimenting with search results in the past, and they continue to run several more tests to enhance the search experience for the user. Earlier this year, Google had launched real-time search where they displayed real-time results from Twitter.
However, they are now taking the real-time search to another level by displaying search results as you type in letters in the search box. Real time search results are displayed when you type in characters into the search box, they continue to change as you type in more characters or use the autocomplete feature.
The new real-time search results as you type was discovered by a SEO consultant Rob Ousbey and posted on his blog, which you can find here. Here is a video of the real-time search results as you type in action below.