I know I've brought this up more than once but I can't help but highlight a new "forum" where people posting messages are given the choice of the context of their post - which also gives the readers some visual context and choice of their own.
TED just launched TED conversations, which looks like it's full of super smart people asking really interesting questions, sharing very big ideas, and guiding fascinating debates.
Each of these prompts brings distinct value in a style of conversation, something I'd like to see more of in terms of high value to this list.
I know we don't have a solution today, but this is something I hope to see for this list in the future!
-Alex