1. You can read the subject summary in a set time 2. You can get involved with no expertise in the subject 3. You will get an answer and an interesting discussion no matter what you have to say 4. Your contributions will help to create an expert summary of the subject 5. You can view the source of any element of discussion 6. You cannot kill the discussion (flooding... trolling...)
Online discussions do not seem to favor good content.
Post how to host a good online discussion: https://medium.com/@hrheingold/the-art-of-hosting-good-online-conversations-38c6d06642d0