Google is really a fascinating company, so when you step back and look at how they evolved, it is both fun and education. Being that I've written about most of these changes over the years, again, looking back at a timeline and a video from the key players on Google on why they made these changes is very useful.
Yesterday, Ben Gomes, one of the key Googlers, posted on the Google blog a post named The evolution of search in six minutes.
Here is the video:
Here is the timeline they published, click on it for a larger version:
I don't have much to add outside of, it is nice to look back to see the direction and where Google may go in the future.
Forum discussion at WebmasterWorld.