Does Yelp Dominate Google's Local Web Results?

A common issue I see with the Google results are the number of Yelp results a Google search can return for a local type of keyword phrase.

It has been going on for well over a year. I even wrote about it when discussing Google's domain diversity.

One webmaster shared an example of a horrible Yelp listing in Google, in the Black Hat Forums.

He said, you should take a look at the search results for [haircut santa monica] and 10 ten results on the web site were from Yelp. Pretty amazing.

Why does Yelp dominate so much of Google's search results? Is Yelp the Wikipedia of local search?