Ask HN: How to offer equity to a marketer?

Hey,

I've been having an surprising amount of difficulty get any decent coverage for a financial web-app of mine; an app I think people interested in finance and investing would love using. Because of the type of app it is, I feel like paid advertising is a poor approach for it. I've been considering offering some equity to someone who is an experienced internet marketer - someone who can get writers, and bloggers to provide good coverage.

My question is, how would you go about offering the equity to someone? I couldn't give it away and hope the person will be successful, and I can't have them do the work and hope I'm satisfied enough to give them a share, etc. So what is the appropriate process here?

Thanks