Google to give realtime search results while you typeAugust 21, 2010: 9:54 PM ET
A blogger caught one of Google's impressive new features being tested.
Google (GOOG) is known to test some of its new features amongst a random subset of users. One such user doing a web search noticed his results page was appearing as he typed and would change as additional letters were added or subtracted.
I imagine this will only work with high-speed, low-latency Internet connections as there is a lot of back and forth from the web page to the server going on in the AJAX.
From the looks of the video however, it seems pretty effective (even faster than my Mac desktop Spotlight search!) and could see a broader rollout in the coming weeks/months. Microsoft's (MSFT) Bing would need to play catchup on a feature like this.
Update: Here's a site that seems to duplicate that functionality to an extent.