Check out this succinct, well-written piece by John Byrne, previously Editor-in-Chief of Business Week: http://bit.ly/eUOobk.
The consequences of us being human search engines are that networks like twitter are winning over engines like google.
Why is this?
Well, Twitter understands that their utility comes from a mix of human and cyber elements - to make one bigger, better algorithm.
Google....well, I bet google understands it too. They just have not put together a social / search offering that has caught fire in the last few years. (Google Buzz, anyone? Google Wave? Hello?...Anyone there?....)
It was unthinkable a few years ago that google might lose it's footing. Just as it's unthinkable now that facebook may falter in the future. But such is the way of things. For now, google remains megalithic. Let's see if they can stay that way.