There are not many people who can honestly say they've changed the world, but Randy Petersen certainly can. The world of travel would be a different place, and certainly worse, without Flyertalk. I wonder how many trips would not have been taken -- and how many would have been more expensive, less comfortable, less enjoyable, etc. -- without it. It would be a truly countless number.
I don't believe that "just anyone" could have started Flyertalk. We've all seen online forums that focus on a good idea, but just fail -- or are seriously flawed -- because of the way they are conceived, managed, and so forth. It's really hard to imagine a better way to run a frequent flyer forum, which perhaps explains why there are no real competitors.
May Flyertalk continue to thrive in Randy's absence! It would be a legacy almost without equal. Best of luck, Randy.