rich! @ etiviti

rich

This plugin is perfect for private message spam prevention. It allows site admin and users themselves to limit exactly who can send messages to the user.
This plugin creates an admin settings page called Restrict Messages. Here the site admin can choose to impose global restrictions over who can send messages to the user.
If message restrictions are delegated to the user, a user settings page is created at Profile>>Settings>>Messages.
Each of these settings pages, depending on which is active, allows private messaging to be restricted to:
<ul>
<li>Friend Connections</li>
<li>Follow Connections</li>
<li>Groups Connections – with further selection of public, private or hidden status levels.</li>
</ul>
The public setting allows connections from all groups to send messages to the user, otherwise private or public stipulate only messages from these types of groups.
Once a restriction has been implements, the plugin removes the private message from the users profile, removes the usename from the compose message send to auto-complete and rejects any messages send where the send to includes an excluded user.
This plugin was originally created by Rich @etivite and is now supported by Venutius.
<h3>Extra Configuration</h3>

BuddyPress Restrict Messages

Exactly what I needed to improve a situation on a client site's, and lovely to see @venutius supporting and maintaining this plugin! Thank you!

Does the job!

This plugin allows the site admin to restrict who can send private messages or to enable the users to choose themselves.

Jonathan Lau

CubePM is a private messaging system for WordPress.
Unlike other PM system, CubePM allows messages to be sent to multiple users and also displays the whole PM system on the frontend using a short-code.

CubePM

CubePM is a private messaging system that integrates right into the frontend of your site.

BuddyPress Restrict Messages vs CubePM