Open Source Business Models

Sometimes I am amazed by open source software... even as I contribute to it. The largest repository of public open-source projects, GitHub, has over 35MM repositories in it. Granted, some large percentage of those are private, and therefore closed-source, but even if only half of those are public, and by all accounts it is much more heavily weighted towards open, the numbers are in the tens of millions. Add in other source hosting locations like BitBucket and sourceforge, as well as privately hosted sites like GNU Labs' git.