Basically, the open-source project became a simple “demo” of not only my code, but also myself. It’s more than testimonials. People in the community get to know you, so you stop being a stranger behind a website. This can change the whole relationship with your customers. It doesn’t have to be focused on price, anymore. It can be built around trust. Compare this to doing work on Elance, for example.
I really like this story. In fact, I stumbled upon this blog from a link to the open source project. For some one starting out, building something useful and sharing it with others may be a great way to establish credibility and gain customers.