This is an extremely simple one-purpose WordPress plugin. What it does, is that if you use Subscribe to Comments, users subscribing to your posts will have a teeny bit of text show up next to their names: (subscribed).
Why would you want this? Well, in the past, you’d edit this snippet of text into your WordPress comment template files. With WordPress 2.7 featuring a revamped comment system, however, this is tricky at best, therefore this plugin.
Obviously you should only install this plugin if you want to reveal which commenters will be email notified when comments are posted.
By the way, does anyone think this plugin is worth having hosted at WordPress.org?
[Update]: Fixed a problem where “subscribed” would show up next to pingbacks and trackbacks.