Online classifieds to sell cars and real estate, common in the U.S. for years, are relatively new in emerging markets. But as Latin American consumers get more Internet savvy, many are going online to shop for houses or autos in much the same way as U.S. consumers use Autotrader.com, Century 21.com and other sites. That's why MercadoLibre (MELI), Latin America's dominant e-commerce platform, continues to move into online classifieds. The company,