Social-media use in the U.S. has reached a tipping point, according to eMarketer estimates, as more than half of U.S. Web users log onto a social network at least once a month. Studies show that as many as 33% of Facebook users and 51% of Twitter users have connected with brands on their chosen social network. Consumers pay attention to brands' social efforts and are giving increasing weight to recommendations or warnings from their peers. "Those who still think that social network users are too busy engaging with friends to notice marketers must change their viewpoint ... Brand interactions are real, valuable and growing," says Debra Aho Williamson.