Your honesty is admirable. But this delves into a much deeper question. What exactly makes you different from every other recruitment house? Companies come looking for talent and pay a fee or a percentage for the people they find. You have a database of talent which is curated based on some way of looking at github commit history. I guess I can see how that can be quite useful when trying to hire someone.

But then from this situation it looks like you aren't getting the type of talent you need to fill the positions you have. So you did what most recruitment firms do. You sent out a form letter trying to get the best talent you could find (like the Director of Security for Heroku) to sign up for your service to keep the companies that are looking for happy.

I am not trying to make you look bad or whatnot. You've already apologized. But I (and I would imagine quite a few others here on HN) use a lot of recruitment services either to be hired or to hire others. Can you talk a bit as to how you plan to be different and find or place that talent better in the future?

it's a dumb only because it failed. will you do it again if the conversion/reply rate was good?

If I were you, i'll probably setup a competition project repo, invite folks to contribute, only do the sales pitch after they are hooked.