Believe it or Not!! Quotes do not have to be attributed. (you see you can write what I just wrote and either put it in quotation marks or not) Attribution and quotation marks simply mean that you are not claiming it for yourself. But check this out: "Believe it or Not!! Quotes do not have to be attributed" (ed 2014); looks better and carries more weight even though we see the apparent authority is full of ..it.
A hard researched collection of quotations attributed is really a pleasure to read, for me.
I write whole hubs with nothing but quotes and they do well for me. All the quotes are mine. But on some I attribute them to me. And I put a bogus copyright notice at the end -- but that is just for word count because it means nothing really ;-)