Who are they? They are the most influential Americans — the ones who tell their neighbors what to buy, which politician to support and where to vacation. They aren’t necessarily who you expect. They aren’t the richest 10 percent or the best educated 10 percent. They aren’t the early adopters who are always the first to try everything. They are, however, the 10 percent of Americans most engaged in their communities — where they wield a huge amount of influence. They’re the campaigners for open-space initiatives and friends of the public library. They’re the Influentials. Together they are the best marketing tool around — using word of mouth to create spirals of influence. With word of mouth increasingly important, they’ve never been more powerful than now. Today, a fragmented market has made it possible for Influentials to opt-out of mass-message advertising, which means that you must take a different route to reach them.