I start with anyone building with my company's OSS tools or contributing to them in a meaningful way. I also look at anyone working on libraries or OSS software

I start with anyone building with my company's OSS tools or contributing to them in a meaningful way. I also look at anyone working on libraries or OSS software that we're using in our projects. Beyond that I scout for people who launch projects from scratch (large or small) as it's a great way to see how people solve problems and how good their product sense is. Sometimes I'll just browse through the top charts on GH in the language we're using. Between GH, Twitter, HN and Reddit I see dozens of projects a day (more than I have time to investigate). One nice thing about doing this is it tends to snowball. Once you hire a high profile maintainer or several OSS enthusiasts, it makes it much easier to hire more. OSS developers will typically be skeptical of "business people", so it's best to either have an OSS presence as a manager or reach out through another OSS dev. I also stress that people can keep working on OSS in their free time (and keep ownership over their personal code). I go into the first meeting prepared to offer the person a job and also offer them the opportunity to interview anyone else at the company they may want to talk to. The results have been very positive, even if they don't take the job. They're usually flattered that you've done the research on their work and value it enough to offer them a job sight unseen. I would estimate that I have ~75% acceptance rate.