When the BBC forums started it seemed great and, for me, directly addressed the requirement on the BBC to support civil discussion and communication. The idea being that people could present their thoughts and opinions and discuss the merits of different arguments in an impersonal and calm way. People taking different sides on an issue would at least be able to see the logic being followed by others, and refine their own ideas if they wanted. This seemed crucial to me after 9/11 with developing crises and wars in the ME. Of course, BBC programmes could also be discussed, providing feedback and interaction to the BBC.
Unfortunately the moderation methods and cost were not taken into account and the boards had to close - those same issues currently affect most of current social media. In fact, few on them even bother to try and have reasoned discussions.
R&E followed the BBC idea and had/has good moderation but just not enough numbers and new traffic through to really make it interesting wrt. to discussion. As the numbers fall I suspect most of us left are really following or posting out of habit. We already know each others views on most stuff and the arguments have been well rehearsed.
To me it has become like the "restaurant at the end of the universe". A place to hangout, post odd quip or joke, and watch the state of the world as it slowly decomposes; will there be a show at the end, a whimper or big bang?