Thanks for responding, Jeff! Yeah, I’ve been very happy to use category topic templates for helping our community to follow guidelines for topics in particular categories.
I feel concerned that I may not have been clear, though. What I am wanting (at least with the first idea in my original post) is to be able to pass in a query parameter to an existing topic such that the text of the parameter becomes the initial text in the “Reply” interface on that topic. So, for example with this topic, if you accessed (something like) https://meta.discourse.org/t/219888?reply_draft=Referenced%20at:%20http://other.example.org/forum/t/17, then this topic would open, the Reply interface would show by default, and the text within the reply interface would contain “Referenced at: http://other.example.org/forum/t/17”.
But I also want to stress that this is just one possible approach to my actual goal, which is to be able to easily allow users to select text from a non-Discourse page and then include that text as a quote within a (related) Discourse post. I’m also curious for reactions on the other aspects of the discussion around this.