I just compared trulia Stats and Trends to the local Multiple Listing Service's stats and trends and Trulia is doing an ok job of keeping true to the market. It seems that their two downfalls are you can't compare your specific home to others like it, and when they mention total # of homes for sale, they mean "listed on Trulia". If you would like specific information, local agents have a tool called Trendvision that can give you more accurate statistics that may be able to give a clearer understanding. I'd be happy to help. Cheers!
The heat maps can be accessed through our Stats & Trends section: http://www.trulia.com/real_estate/Placerville-California/
If you access that page and scroll down, you'll find the option to view the Home Prices Heat Map for your area.
Please let us know if you need further assistance or have other questions.