First versions of Absolute Comments implemented several features that are now, out of the box, part of WordPress.
Absolute Comments now simply adds a “Reply” link into comment notification emails, prefills the comment reply with the commenter’s name, and adds a few cute icons.
There’s no option or settings: just activate and forget it’s even a plugin.
Official page: <a href="http://planetozh.com/blog/my-projects/absolute-comments-manager-instant-reply/" title="Absolute Comments" rel="nofollow ugc">Absolute Comments</a>
Tip: To keep track of this plugin’s evolution and features, you are advised to subscribe to the <a href="http://planetozh.com/exit/feed" rel="nofollow ugc">author’s feed</a> or follow him on Twitter: <a href="http://twitter.com/ozh" rel="nofollow ugc">@ozh</a>

Ozh' Absolute Comments

Reply to comments from email notification

Jennifer M. Dodd

bbPress Threaded Replies is based on comment-display functions from WordPress 
and topic-display functions from bbPress. Settings can be adjusted on the bbPress 
Forums options page of WordPress. bbPress running as a WordPress plugin is required.
bbPress Threaded Replies is incompatible with the Fancy Editor; enabling threading will 
automatically disable the Fancy Editor.
The plugin checks first in the stylesheet and template directories before reverting 
to the default plugin templates.
<h3>Credits</h3>
Development funded, in part, by Ariel Meadow Stallings and the Offbeat Empire.

bbPress Threaded Replies

Add threaded (nested) reply functionality to bbPress.

Ozh' Absolute Comments vs bbPress Threaded Replies