I can never quite figure out why advertisers always so insistant on new media, particularly social media advertising. Depending on who you ask, a properly run twitter account can blast your small company from an unknown to a household name. I doubt that a proper media planner would ever say something like that, but there are always people who are willing to sell snake oil to desperate people.
The problem however, is that mediums like Twitter, Facebook, and other social media sites are voluntary media. No one will be forced to visit your twitter page, and in fact, what these mediums should be used for are as a means to develop a relationship with the consumer base that you already have. Give out promotions, lay out some fun facts, if your an entertainment company/person, doll out a few behind the scenes things, and all the more foster your little club of followers so that they are rewarded for their continued brand loyalty.