This is more of a FEEDBACK to bring a new feature.
Let's say I paste a perma-link of an accepted answer from one question to a different question and I did that today - How to check file/directory permission with Zend.
But one of the user commented me saying "We are not supposed to copy content from linked duplicates as answers." which I didn't, I know the question is a duplicate, and I mentioned that on the answer with the link to the accepted answer on duplicate question. All I did was copied the accepted answer on the duplicate question and pasted it on my answer with label: "Quick Info" kind of quick glance to the answer from the link.
The comment from another user triggered me to post a feedback to SO asking to give a feature where one post a perma-link of any question/answer should show the glimpse of it's answer.