What happens is namely that I get a page that looks like google.com. Big whoop. And considering that the URL contains the string "chromeexperiments" I didn't immediately realize that I had to open it in Safari instead of Chrome to see the effect.
For others in the same pickle: The effect is that the DOM elements fall down, as if there is gravity.
EDIT: I just noticed this won't work in Safari, but it will work in Chrome.
In this, the motion and positioning are somewhat arbitrary/random. (Well, later query results pile on top like sediment, but it does not otherwise appear that the acceleration/velocity or start/end positions are indicators of result type, relevance, etc.)
My guess is that with the rising ease of animation on the web, motion (and changing scale/rotation/etc) will increasingly be used as a substantive indicator -- not just a transition or flourish. It will give extra hints of the underlying values or data structure. For example, the most relevant search result might wiggle a little... or results that tilt or vibrate in varying directions might subtly hint at ranking according to a secondary scale.
Of course this can be overdone to the point of obnoxiousness... but sprinkled in, maintaining a high data-motion ratio (like Tufte's data-ink ratio), such animated text will seem natural to the screen medium.
This was somewhat possible via a <blink> tag back in 1996 or so.
