Word-for-word copying is only allowed as evidence / supplementary material, and even then must be properly quoted and attributed.
A quote should never be a full post, attributed or not, and presenting it as one's own is strictly forbidden.
Someone recently posted a comment suggesting (as I interpret it) that this doesn't apply to content in the public domain or under a creative commons license not requiring attribution:
Well, if the original post is marked with a public domain or creative commons license, it shouldn't be a problem.
You can see my response:
I'd still expect users not to present public domain work as their own, and especially not as the entire post. If a good source can be identified, that should be cited; if it's all over the 'net, the post should at least acknowledge that it was from widespread public-domain content.
But (much to my surprise) I couldn't find a policy to point him at that explicitly addresses public domain work, so I would like to clarify the network's position on explicitly requiring users to present public domain works as a quotation and not their own.
So for the purposes of presenting this as a discussion, should users be required to present public domain text and text licensed in some manner not requiring attribution as a quote and not their own?