What Does 'Engagement' Do?

“Engagement” has become one of the more enduring buzzwords of recent years. It started as a vague term tossed about by publishers and then advertisers to indicate some heightened state of communication or interaction between a brand and a consumer. Recently I have heard it made into a more specific noun. Interactions with customers are sometimes called “engagements.” To some degree it is an article of faith that engagement is almost an end in itself. But what is the actual effect of engagement? Do different kinds of engagement produce different behaviors in consumers? What needles does this marketing nirvana state actually budge, in the end?