The flip side of the iceberg

We all know (at least most of us do) the iceberg view of the dissatisfied consumer (basically and in broad terms, for every consumer that voices dissatisfaction to a given company, there are even more dissatisfied consumers who will not contact the given company and will talk negatively about the given company to their friends).
One obvious benefits of monitoring social media and engaging in social media is for marketers to react quickly and provide a response to anyone who broadcast their issue with a brand and thus in a best case scenario giving marketers a shot at turning these vocal entities into brand advocates...
and we pretty much all know this by now...
The flip side of this however is for marketers to understand and quantify how the positive experience is being voiced and the iceberg structure behind the positive advocacy and finally how it compares to the negative iceberg structure.
I heard at the e-pharma summit last week, that basically 60 to 70% of social network comments related to a brand are usually positive. That's a good start. But knowing the iceberg structure behind the positive voice is what we need to understand, that is: for every consumer that voices a positive experience, how many are saying something online? How many are not saying anything to their friends and how many friends are they? How does the brand advocacy iceberg compares to the consumer issue iceberg?