Related to my How do I create a custom post type for a training CMS in WordPress? question, I would like to know how I can create a private comments section for a custom post type (or any post type for that matter, if possible), where these comments are only visible to their author. I am working on a training CMS and students should be able to make private study notes on the training content pages as they work through them.
Comments have an associated author to them.
In a section called "Private Comments" - Query for all comments belonging to the current post where wp_comments->comment_author_email equals the email of the current user.
Checkout the wp_comments table. It has 15 or so fields you can filter when displaying comments.
EDIT: The code would look something like this:
You loop through the list of comments for the current post and filter by author email.
You don't need to add a metabox, just amend the code that displays the comments - the actual code you will need to replace will depend on which theme you are using.
However, please note that you should avoid comparing the comment e-mail address with the current logged-in user e-mail address as suggested above as a registered user can change their email address. This does not then change the email address used on existing comments so only comments made after their email address was changed would be displayed.
Probably better to compare user-IDs: