So, I'm launching soon my startup and I need early adopters (entrepreneurs) to test it and give feedback to improve the platform. I want to create a slack group or a facebook closed group, so the users can enter see advances of the platform, report problems, make networking and make suggestions.
I think a Facebook group is better because many folks already have accounts on the platform and have access from their mobile too. So you can keep the discussion alive. Whatsapp group is another way of doing this.