Reach: How far information will travel across the social continuum. More popular topics will travel farther. Think of it as the size of the wave of a tsunami.
Relevance: Alignment to interests of the moment. Relevance is situation sensitive; what is relevant to someone after taking a vacation is quite different to what was relevant before booking that trip.
Resonance: The ripple effect of information. It determines how long a conversational thread will remain topical or how many people feel compelled to offer their opinion in the matter.
