For those posts about flame throwing and starting the fire:
[ame="http://www.youtube.com/watch?v=WHwMtFERcQY"]YouTube- Billy Joel- We Didn't Start The Fire[/ame]
As for the OP, I'd say that I observed on two INFJs that I know irl, and lots of people I know said that they observed that I too have the same impact on people, is that the moment that they walk into the room it's like the energy of the people present calmed down a bit, and I observed that people I know usually turn to me when they need some kind of mediation.
Also I've noticed that many people turn to us when they need to calm down or to bounce of some ideas to get a clearer picture about things that matter to them, which can be a bit draining but we seem to be exceptionally good at it.
Other than that, it could be, as previously stated, charity work, involving in revolutionary ideas and being the silent leader in things.
That's all I could think of at the moment.