Trulia is a is not that old. That being said, there are a lot of brokerages that don't have a direct feed to Trulia yet, there may even be some boards that aren't compatible. In this case the agent would have to enter the listing manually. I know that in my area, there are a lot of agents that don't know what Trulia is. Our listings, from my office, are on an automatic feed in. When I talk about Trulia, agents in my office look confused and dazed. It makes me believe there is still alot of growing for Trulia to do!