Isn't most of it about having something public you can talk about and show your contributions for? It's not a filter in and of itself, but almost all of your o

Isn't most of it about having something public you can talk about and show your contributions for? It's not a filter in and of itself, but almost all of your other experience will be proprietary and closed, and you can at best talk in generalities about problems you've solved. You can't evidence half of it. Open source projects allow someone who's umming and ahhing to have something concrete to see whether or not you're selling them donuts. Certainly isn't a requirement though.