What are the exact requirements for BETA-stage and where can I read about it? Thank you :) I am asking, because I am preparing for entering the BETA for LBRY Protocol.
You are still a long way from beta. After Definition phase is Commitment phase.
I would suggest searching through discusions for 'beta' https://area51.meta.stackexchange.com/search?q=beta to learn more.
To answer your question, take a look at http://area51.stackexchange.com/?tab=beta&page=2 the beta site Board and Card Games, has been in beta for 2800 days!
But if you are not expecting many questions, it will make getting through private beta difficult. Assuming you get 200+ users with 200+ rep on another site to make it through Commitment phase.