In 1994, Li joined IDD Information Services, a New Jersey division of Dow Jones and Company, where he helped develop a software program for the online edition of The Wall Street Journal. He also worked on improving algorithms for search engines. He remained at IDD Information Services from May 1994 to June 1997. In 1996, while at IDD, Li developed the Rankdex site-scoring algorithm for search engine page ranking, which was awarded a U.S. patent. He later used this Technology for the Baidu search engine.