Very good point. We certainly don't want to go broke!
However, we feel very strongly that Watsi should be run like a successful startup, and not like a traditional non-profit.
Sustainability is extremely important to us. I'm a terrible fundraiser, and I want nothing more than for us to cover our own overhead.
However, it just doesn't make sense to implement revenue generating features (e.g. take a cut of donations, which to be clear we will never do) until we hit scale. Right now, we're entirely focused on improving our product, speaking with donors, and maximizing our impact.
However, just like any successful startup, there will (hopefully) come a time when the costs associated with scale begin to outstrip the seed-support we've so generously received from people like pg and Jessica. When that happens, we will implement features that generate revenue for our organization, and we'll have a user base large enough to make those features viable.
Without going into too much detail, those features will include things like asking donors for an optional "tip" to Watsi when giving to a patient (expected to net 6-8%), cause marketing products (already a few companies interested), white label, etc.
We will never abandon the 100% model, and I'm completely confident that for as long as there is demand for the service we're offering, we'll find a way to cover our overhead.