For some reason, I remember there being revenue or employee number requirements for participation, but I may be misremembering? Perhaps it was discussed on GH [0] but never put in place. I'll admit I wasn't following the conversation too closely but I was trying to stay in the loop.
All I can see on the website [1] right now is:
> The minimum to participate is $2,000 per full-time employed developer per year.
Is that it?
[0]: https://github.com/opensourcepledge/osspledge.com/issues/45