When I was co writing a blog, social media was our primary way of promoting the blogsite. I don't remember the figures anymore but it is substantial and we were sure that the traffic was due to the promotion in Facebook. Even now, Facebook is more potent considering the number of active users in my friend list.
Ofcourse! Depending on your purpose or usage of social media. For me, I use it for learning new things that I can apply when I go back home for good. As an OFW, it's a big help and very relevant in our daily life bridging the information all over the world and knowing the latest that we could acquire.
I think social networks do help. There are many features on facebook for example that allow you to purchase more audience reach. I am not so sure about other social network sites but I do know twitter is very popular for marketing too.
Honestly, I don't think so. Many forums or websites got their own popular pages. Still, they barely get enough members from social networking sites. People like following or liking content in the social media sites but that's about it.
They don't really join the website or forum. So, I don't think social media would help any forum in getting new members or in gaining popularity.
Sometimes, I really hate social networking sites for the very same reason.
Social network is good depending upon how you use or what you share. But if Facebook pages, aren't popular now a days because people don't care to visit your website, they just like your page and see your post on facebook itself.