Actually I don't see an easy way to do it for Mudcat users. (Does anybody have an idea?)

If the Mudcat script were open to improvements, I would propose a button at each post, saying "Copy a link to this post into your clipboard". The text will be pre-filled with "this post by ***". In other words, when pressed inside Joe's post on 27 May 25 - 08:17 PM, the clipboard would be filled with

<a href="thread.cfm?threadid=120999#4223333">this post by Joe Offer</a>

- which users can insert into their own posts unchanged, if they don't dare to edit it.