That is a great question. It is free for brokers to include their inventory on our site. Therefore we display most of the inventory in many markets. For example in Brooklyn we work with every C21, Coldwell Banker, ERA, Sotheby's broker, as well as Independent firms like Community Homes sales, Aguayo & Huebener, Fillmore Real Estate (Brooklyn's largest Broker), Brenton Realty, Prudential Dougals Elliman and more.
Any broker who does not appear on here just needs to submit their site to be indexed, for free by us and we will include them. Therefore since the barrier to enter is so low, we do have most of the market in one easy to find place. As time goes by more and more brokers join our results, so you can expect more names you know to be joining us soon. If not just let them know that it is free to be included in Trulia results.
The link below explains how we work with brokers across the country.
So we are NOT just a paid ad site, and we are definitely providing great tools for real estate consumers to find relevant local real estate information. Including past sales history, and active for sale listings. Sadly there is no public service that has ALL the listings, especially in NYC where most of the largest brokers are independent and not even in an MLS - go figure! :) But we're pretty close...