WPML - Buddypress

BuddyPress is a social network plugin for online communities. With it, your users can register, create user profiles and groups, have private conversations, and interact within the community. You can choose which components to enable with your site, or pair BuddyPress with one of the many themes or add-on plugins built for it to create a fully customized, robust experience for your members.

You can set the profile visibility, set up public or private messaging, display activity streams, set notifications, and use the emails API to create and send emails to your members. BuddyPress is fully compatible with bbPress to create forums.