Unknown on Trulia is pretty meaningless. The problem with Trulia and Zillow and others is that the listings are often found someplace else and automatically posted there on those sites to add to the amount of listings. They are often out of date and many are sold months ago and never deleted or updated. When you are serious about finding homes you need to contact a local Realtor to feed you real and up to date listings and not rely 100% on online sites not matter which ones. These site are good to get an idea, but badly out of date sometimes.