This site demonstrates the Comment Subscribe Module and its functionalities
Take a look @ the content generated through devel module, and check out the comment subscribe features.
You can view the generated dummy content here http://demos.zyxware.com/comment_subscribe/node
If you login with the below provided credentials you can create your own content to check out comment subscribe.
The Comment Subscribe Administration Page is made available for a logged in user.
User Name: demo
Password: demo
Report Any bugs back to http://drupal.org/project/comment_subscribe
Thank You
Zyxware