BuddyPress Private Reply gives your users to “private reply” to any post in the activity feed. The plugin adds a “private reply” button next to the traditional reply button. A user simply types in their reply as normal and then clicks the “private reply” button. The message is now only able to be seen by the person that posted the reply and the original post author. Private message replies will show up in the activity stream with the words “private message” next to the message so both users (the person replying and the original post author) so each will know it was a private reply. The private reply will show up in the same activity stream as the public replies.
You can visit the demo and login with:
1. Extract the plugin archive
2. Upload plugin files to your /wp-content/plugins/ directory
3. Activate the plugin through the ‘Plugins’ menu in WordPress