AWPCP uses a “double blind email system” similar to Craigslist for users and posters to contact each other.  They do this through the Reply To Ad form, where the user submits the data they wish to send to the poster, and your WP site sends the email on behalf of the user to the poster.

The Reply To Ad page is used to create the reply form when a user clicks on the “Contact <name>” link inside of an ad, such as this one:

Once clicked, the Reply to Ad form is created with the context of the ad:

This particular page can’t be visited outside of the workflow process for AWPCP.  You should not delete this page or make it private from your site, although you can prevent it from being displayed in the menus to avoid confusion from your users.