PR 2.0 is the science of influence by going direct to consumers and end-customers, by-passing traditional media influencers. It recognizes that people now trust peers more than authority. In contrast with the mass communications style of the traditional public relations, PR2.0 creates influence by starting, joining and shaping conversations. PR2.0 creates influence through one-on-one conversations which result in ripples of powerful word-of-mouth.
Social media is one of many channels of influence. Others include the large number of wires, Google Alerts and RSS feeds which all take unmediated news directly to consumers/end-customers.