[PricelessValue]

>1. Who "started it"

Not just who started. The quality and sophistication.

> 2. How long they've been doing it 3. Percentage of people affected by it (not number!)

Yes. What else would it be? What other metric would you use?

[rconti]

"Leading" implies, to me, sophistication, how widespread it is, and how many people it impacts.