I did not mean to say that - "No body will join if there is no facebook page" .
Plz dont misunderstand . Rather I am saying like if there is a facebook page , it would be lot easier to reach more people . Thats how social media works . Now q2a getting traffic from organic search from google and from some other websites where they mention about a well developed forum software .
For developer prospective it does not really matter if there is a facebook account or not , but for them who dont have any idea like there is a awesome software like this or not it would matter . Also for giving updates , keeping users engaged social media is the well proved way .
If you have not seen the official facebook page of stackoverflow you can see it here -https://www.facebook.com/officialstackoverflow