This is an interesting comment from Peter Norvig [1] over at google.

"We (once) thought of ourselves as observers of the Web. We made a copy of it, and we thought it was just a reflection of the Web," Norvig said Sunday while speaking here at the Singularity Summit, a two-day conference on artificial intelligence. "Now we understand that we're co-evolving. When we make a change, it changes. Search engine optimizers watch us, and when we make a move, then they make a move. The Web moves in different directions because of the interaction between us," he said.

So, there they are, looking for a Nash equilibrium.