According to me you can promote your business by using the Google and yahoo for local search these are the best service provider..the Google strategy in terms of SEO is a lot different from that of yahoo or bing..Google has a much better social media record site than that of yahoo because of YouTube. With the implementation of Google Buzz as the new social networking site of Google, Google aims to dominate and promote their website in a way that it combines all the factors that Yahoo..
So i think google is best of best..