As of late I’ve been getting reacquainted with the thinking of Professor Eric von Hippel of MIT, who studies the innovation process.  It’s intriguing stuff.  Here’s an excerpt from his paper "Breakthroughs to Order at 3M":

Not all users are created equal with respect to the development of commercially-important innovations and innovation prototypes.  Research shows that almost all user-developed ideas and prototypes of general commercial interest tend to be developed by “Lead Users” – that is, users that: (1) expect to get high benefit from an innovation and so have a strong incentive to innovate and; (2) that are ahead of a target market with respect to one or more important trends…

The point is, if you want to find users that are actively exploring and testing new ideas, it is a waste of time to survey users in the center of the target market.  Instead, you must develop methods to seek out users that are at the leading edge with respect to needs that are important to that market – even if such lead users are rare and hard to find – because that is where interesting user idea generation and innovation is concentrated.

You can see more of his writing here.