User Messages will allow the users registered on your blog to have a private Inbox on your site.
WP Mail plugin is simply a wp network mail or message system. User can send mail or messages to other users over one wp network.
Admin User Messages is a simple plugin that allows communication just between Admin and single users, but not a communication between user and user.
Version: 1.5.01 Adds a widget option showing the three most recent private messages to logged in users of a BuddyPress powered website.
Display stats from your email inbox.
Replaces wp_mail and sends email the right way so it does not get flagged as SPAM.
A plugin that allows you to organize ideas for future blog posts, plugins, anything at all in one simple page under Manage > Ideas.