Don't let another comment go unanswered! When commenting in Google Docs, add a "+" in front of a collaborator's email address and they will be sent an email notification, if they have a Google account.
More directions are below:
Direct a comment to a specific person
To make sure that a specific person sees a note meant for them, you can address a comment to a specific person so that they receive an email notification about your comment.
- Open a document, spreadsheet, or presentation.
- Highlight the information you want to comment on.
- Go to the Insert menu > Click Comment > Type in your comment.
- Somewhere in your comment, add a + plus followed by the email address of the person you want to see the message, for example: +johndoe@google.com.
- Click Comment to save the comment.
If the person in the comment doesn’t have access to the file, you will be asked to adjust the sharing settings on the file to allow that person to see your comment.