Social media has become an almost unstoppable presence for a number of reasons - the same reason businesses must give it an ear - and a mouth. It's a binding phenomenon, often brining users with like interests together, ignorant of geography and technology. People engage in social media (just look at the numbers). It crosses the social barriers traditional advertising have often struggled to overcome, relying on interpersonal relationships to create links. It's simple, quick, and cost-effective. It's measurable - with the right technology businesses can easily determine the effectiveness of their social media efforts.