There doesn't seem to be  definition of it on the site.

I have seen various posts of mine being taken to task because they are put up as "opinion", but some people systematically ask me for "proof" or "links" or "sources" or whatever in order that I justify what I write!!

I can understand that attitude when it's directed towards "news" posts, but I put up opinion posts. That means I put up my own opinion only. People are free to buy it or not.

So why do I have to justify them?

If people have other info they are welcome to put it up in comment, but I do not like this tendency which consists of commenters asking "opinion" posters to "justify" what they post. Smells bad..

Think about it...................................