The Hackathon Hackers Facebook group is pretty active with 35K members: <a href="https:&#x2F;&#x2F;www.facebook.com&#x2F;groups&#x2F;hackathonhackers&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.facebook.com&#x2F;groups&#x2F;hackathonhackers&#x2F;</a>