http://test.com SAN FRANCISCO:Facebook said on Wednesday that it is displaying ads from a small group of marketers on other companies' smartphone apps, the latest sign that the world's No. 1 online social network is closer to launching an ad network business. Facebook said that the test is currently limited to a "few" advertisers and mobile app publishers. "Our aim is to demonstrate even greater reach with the same power of Facebook targeting for advertisers both on and off Facebook," t