Wall of texting.
It seems to me, in the some of the more controversial and technical/academic discussion (ie. economics), it's common for people to wall of text/post lots of massive posts, often bringing up non-relevant tangents .
This obfuscates the the discussion, as people need to then wade through it all, and it's easy to get distracted discussing a tangent, rather than the core issue.
I think it's better try keep your posts focused, and minimal; try keep the discussion to one (progressive) line of reasoning at a time.