The Possible duplicate auto-comment is pretty bare bones right now; just "Possible duplicate of [title of duplicate as link]".
I've noticed since we can now only close questions as duplicates of answered questions, we can make the comment a bit friendlier; it's not just a dupe (sadface), it has my answers (happyface!). Waxeagle suggested something similar to this, a comment of his own. Here's another possible wording:
This question appears to be a duplicate of [link] which already has [n] answers; see if you can find your answer there or edit your question to clarify why those answers do not suit your situation.
The edit bit is something extra I often throw in when I'm only 90% sure a post is a dupe, to see if I can goad more details out of the asker.
There's also two edge cases that allow dupe close votes without the souce question being answered; should probably still get the old comment form. These cases are MSO questions (any question can be voted as a dupe without answers) and where the dupe is also posted by the same user. In fact in that second case the auto comment could be something like:
This question appears to cover the same ground as your earlier question [link]. There's no need to repost, if you need to update your earlier question simply [edit it] (link to edit original Q).
