As expected, MSN Tuesday launched the U.S. pilot of its paid search product, dubbed adCenter. The pilot will have 500 advertisers, whose ads will be served for 25 percent of queries on MSN Search;
sponsored links for the other 75 percent will be populated by Yahoo! Search Marketing, which has a contract to power MSN's paid search through next June. The adCenter product was initially piloted in
Singapore and France, and launched officially in those two markets last month.