One idea is to build a track record the way most hedge funds build a track record, right? Trade assets, record your annual return, and whatnot. You could even run a regular old hedge fund and make a bunch of money. Then when you started getting some credibility, give away your insights for free.

(Personally, I'm not convinced that you'd do more good by giving your insights away for free than you would do by keeping your insights secret and donating the money you made to effective charities, but I'll listen to anyone who wants to persuade me.)

By the way, if people on LW want to start a hedge fund, I'm interested. I'm not a mathematician, but people seem to think I'm pretty solid at programming.