While there continues to be talk of a cohesive statewide MLS, at the moment and likely for the next decade, your best bet is actually a combination of Realtor.com and the MORE system (thanks John!).
Trulia, and many other "MLS websites" are not true MLS'; but rather, syndication websites that re-post MLS listings from true RealtorÂ® MLS systems. If you are interested in the "whole story" see:
MLS Data Accuracy â€“ Where to search if youâ€™re â€œwithout RealtorÂ®â€
Realtor.com will only show current Active listings and Sold properties for a limited time. Once a property goes Pending they remove it from the database (and will show it again if the deal falls through). For privacy and security reasons they do not keep detailed past Sold listings on the site; however, they will show limited data (a few details and a satellite property view) on "recently sold" property for about 6-8 months after close of escrow. [By the way, try Realtor.com's new GPS-enabled mobile app that allows you to draw on your mobile device with your finger to find active listings.]
The other thing you should know is that Brokers have the right to control syndication and the fact is that many Brokers, and AORs, across the US are revisiting/scrutinizing their data-share relationships with 3rd party syndicators/aggregators. So, getting to 100% data integrity is unlikely.
However, in June of 09 I spoke with the NAR Liaison to Realtor.com who informed me that 99.99% of AOR MLS listings are automatically fed to the national http://www.realtor.com
website. (I followed this up with the VP of Industry Relations for Realtor.com who did not disagree with this estimate). Do I believe this percentage has dropped? Sure, minimally, but in general, Realtor.com is not a bad choice for Active listings; especially when coupled with the MORE system.
More about MORE:
The Multiple Organization Reciprocal Exchange is a reciprocal data access initiative that provides members direct access to MLS systems covering 21 counties in Northern California. MLS Partner Systems and
SFAR covers San Francisco
BAREIS covers Marin, Mendocino, Napa, Solano, and Sonoma
MetroListÂ® covers El Dorado, Merced, Placer, Sacramento, San Joaquin, Stanislaus, and Yolo
MLS Listings covers Monterey, San Benito, San Mateo, Santa Clara and Santa Cruz
The systems may not be perfect, and you will still probably have to continue to ask your Clients â€œWhere did you find that property?â€ on occasion; however, if you use a combo of the Realtor.com / MORE system you will be doing it less.