I came to suspect, by the way, that a site like mine would be useful primarily for a particular kind of open-source project: one large and mature enough to have

I came to suspect, by the way, that a site like mine would be useful primarily for a particular kind of open-source project: one large and mature enough to have a significant user base -- a significant commercial user base -- yet not so mature that it already does most of what its users want, nor so large that it already has a well-known business supporting it. The best example of such a project I can think of offhand is D. It might be interesting to ask Walter Bright specifically what he thinks about this or would want in such a site. I also think it's important to understand what the value is for contributors. I think we both have the same observation here: one thing an open-source developer has to sell is their choice of what to do next. Imagine a developer using an OSS package and trying to get their manager's approval to spend money to get some bug fixed or some new feature; they have to have a good answer to the question, "why are we spending this money?". After all, it's possible that if they just wait long enough, the fix or feature will appear anyway. And I think generally, the answer is that by offering to pay, they influence the developer's choice of what to spend their time on; this gives them an incentive to offer an amount related to the cost, to them, of not having the fix or feature.