Marketing program measures have traditionally been discussed in terms of reach, awareness, GRPs, and market share.

Of course, sales should not be the ONLY marketing objective.  But, as secondary indicators, consider some old measures in new language or skin:

Credibility vs. Trusted Source
Referral vs. Pass-Along
Viral Impact vs. Creative Impact

Zealots – referral agents – are themselves a valuable form of media.  And, they are simply more credible than any other form of media available to marketers. Factor credibility into your marketing planning and see if you don’t look at referral and social media in a new light.