Whenever someone post comment in your WordPress site you automatically receive an email notification by WordPress. If you are a regular in blogging and your site is getting a lot of readers then this auto mail becomes irritating because you already get notified about the new comment in your WordPress dashboard.
You can stop this Email notification for comments very easily without using any plugin or hack. Login to you site. From Dashboard scroll down to Settings menu and click Discussions. Then, scroll down to email settings and uncheck the options as shown in the following image: