That makes sense - the copyright comment regarding the registered trademark symbol.
Isn't the Copyright symbol a C in a circle.
But the submission of writing into a discussion forum which includes TOOLS such as a QUOTE BUTTON, may be a voluntary contribution for FAIR USE in the entire site's forum.
I had put a copyright note on a posted article of mine, at a tree forum this week, but dropped the copyright notice, because I had voluntarily DEPOSITED my artical into the MACHINE so to speak.
If no one removes my artical from the forum, then I consider it as fair use.
There are fair-use exemptions - like photcopying a page from a book, but I'm not an expert on the technicalities.
It may be more likely than not, that moving text from one part of a forum, to another post, would qualify for fair-use exemption.