I saw an old post about requesting a referral program. Im in the same boat- I manage two PhD groups, 1 on Facebook and 1 on LinkedIn and would be interested in something like this. I love your product and will share and recommend it regardless, but wouldn’t mind fringe benefits 
Welcome to our forum, @Christian_Brielmaier! We don’t have an official referral program, but please drop us a line via chat or email (support@paperpile.com) and I’ll connect you with our billing team to look into alternatives.