WordPress’s comment system is very basic. After someone comments they really have to either sign up to your comments RSS or come back often to see if anyone has replied to their comment. A very useful plugin that helps make your comments area more useful is the Subscribe to Comments plugin from txfx.net. This simple plugin adds a checkbox to the comment entry area that allows users to subscribe to that page/post’s comment list and receive an email whenever someone adds a new comment to that post. Considering that this is such an easy thing to add in, and usually requires no editing or code changes to work, it’s a no-brainer as a required addon for most WordPress sites.