Some people are too lazy to type out full usernames in @replies, and they don't use the autocomplete either.
This script is for these guys--it leaves the job of being lazy to the script. Now you can be too lazy to be lazy!!
All it does is add "reply" links to comments, except that it puts a concatenated @reply--with only the first three letters of a username.
Click here to install. Will only work in Chrome or Firefox (the latter requires Greasemonkey).