Zipf's law applies to more than just the letters in the alphabet. In just about every system and every market, a power law is in force.
Heavy users make markets work. There are a few people who eat out every night, or go to 30 Broadway shows a year, or send 200 greeting cards annually or buy $100,000 worth of jewelry at a shot. There are people who tweet every three minutes, individuals who work to have tens of thousands of Facebook fans or work overtime to be the top of the heap at door-to-door selling.
This is a given. Your power users will account for a disproportionate amount of your usage and attention.
The question is this: Is your project organized so that it benefits from the power users? (And so it benefits them in return?)
In the case of Broadway shows, not at all. Frequent ticket buyers do nothing at all to help the marketing or impact of a typical show. On the other hand, Twitter is designed from the ground up to grow as their power users push it forward. Wikipedia thrives on the work of just 5,000 power editors. eBay grew because just a few thousand home businesses used it as a platform to bring in millions of buyers.
Power users can pay you more or they can build infrastructure, or they can do outreach for you. The challenge is in finding them, embracing them and giving them tools to accomplish their goals as you reach yours.