I am looking for a feature that makes it possible to reply to comments, or mention users in a comment using the @ symbol.
So, if I was to write the following in a comment on a node:
@Michael Jackson Cool stuff dude.
"@Michael Jackson" would turn in to a link that leads to his user page.
Also, if it is possible without to much hassle, it would be great if it only turned in to a link if the user exists, to prevent a 404 error.