Real estate data firm Trulia launched its Social Search function this week to digitize word-of-mouth referrals for agents using Facebook. The platform allows customers to endorse an agent through the Trulia website and their Facebook page. The endorsements then turn up as a personalized list of recommended agents for customers searching Trulia's agent directory. The system publishes the recommendations through the agent's Trulia profile, the customer's Facebook page and through Facebook news feeds linked to those customers. "Real estate professionals have long since cited word-of-mouth and referrals as one of their primary sources of business," said Georg Gerstenfeld, Trulia senior vice president of business services. "Trulia Social Search provides a more efficient way for agents to receive digital referrals from their clients, maximizing their reach with each recommendation they receive." Pete Flint, CEO of Trulia, said "consumers prefer endorsements from a family member or a friend over anonymous reviews or ratings." Write to Kerri Panchuk.