You can choose to allow or disallow comments on each post or page that you write. To allow comments on a particular post, make sure that the box next to “allow comments on this post” is checked. You can find that box under the main textbox for the post. Here is a screenshot:

This setting may also be set globally by going to Settings>>Discussion and checking or unchecking the “Allow People to Post Comments” box.  When you do this, the change will go into effect for all posts made in the future.

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