Here is part of a recent article by by randfish of SEOmoz
In a number of sectors, certain sites have had dramatic success over the years and maintained it. Looking at these domains and understanding their strategies is an excellent way to bolster your knowledge of how to play this competitive game. Some of the sites that have impressed me the most on this front include:
I'll leave it to you to run the queries, see the success they're having in local rankings and reverse engineer their strategy.
- Yelp & Urbanspoon in restaurants
- Trulia, Zillow & Yahoo! Real Estate in real estate
- Superpages in doctors and dentists
- Freelancedesigners for programmers