Alex Krupp points us to this neat post from Jackie & Ben: Church of the Customer Blog: The 1% Rule: Charting citizen participation.
The upshot is that for many organizations, the top 1% do 80% more of the contributing. The fascinating Wikipedia example (fascinating for me, anyway) points out that after about three and a half years, Wikipedia had just 15,000 contributors. But 4,000 or so of them did almost all the work.
Often, it's easy to imagine that big companies like Hallmark and British Airlines and Coke are selling lots and lots to everyone. In fact, a tiny slice may very well be the difference between success and failure.