The difference is that the users buying the product (eye balls on search) value it differently. This means you can get your first 1m users without needing to be as much better (maybe you can even be worse) than Google as you would otherwise need to be.

It's a very interesting problem. When starting a company the biggest problem is often getting the first few users. One option is to build something people want - another is to build something your friends want - but another option is to build something the media wants to talk about.