NOTE -- Box Notifications are not working; this is on the Box Know Issues List. Check here to see if the issue has been resolved. https://support.box.com/hc/en-us/articles
The "comment" feature on Box allows users to improve work flow efficiency by providing a standardized location where users can communicate, log changes, and assign tasks. Click here to learn more about adding comments and tasks.
Depending on the notification settings assigned to the collaborated folder, users may or may not receive email notifications when someone adds a comment or a task.
Help! I'm receiving emails every time someone comments on our collaborated files
1. In Box in a web browser, go to your "Account Settings" located under the User Profile tab
2. Select the Notification tab
3. Scroll to the "Email Notifications" section
4. Uncheck the "Comments" box under the "In folders I've joined" column and click "Save Changes" 
- You will no longer receive email notifications when new comments are added to folders where you are a collaborator.
I need to be notified when comments are added to my collaborated files
Box can send notification emails regarding any activity performed in users' shared Box folders. This function will notify users when folders (and files in folders) are downloaded, uploaded, commented on, previewed, or deleted. Users can set default notifications that will apply to all folders they created or all folders they are collaborators on. Users can also set notification settings for specific folders that will override their default settings. Click here to learn more about setting notification preferences.