Any 1 Plugin for Notify about: Comments & New Posts

I am looking for 1 Plugin which offers following 2 features to visitors commenting:

1) While Commenting, visitor can Subscribe to – New Blogs Posts (via Checkbox)

1) While Commenting, visitor can Subscribe to – Reply to Comments (via Checkbox)

I saw generally these features are provided via check box. Visitor can click on the Check box to Subscribe to New Blog Posts & Comment Reply.