User Management

Wildfire adds refer-a-friend functionality to Drupal. Users refer others by email, Facebook, and Twitter.

This module sets a simple limit on the total number of users that can be added to a site.

While I suppose there might be other use cases, mine involves being able to set a quota on the total number of users in a site being managed through Aegir.

Query hundreds of millions of social web profiles by email, Twitter username or Facebook ID.
Supports results from over 125 social networks.

This module integrates with the Qwerly API to enrich Drupal user profiles with social media profiles so that enterprise owners can learn more about customers and leads.

Contributed and maintained by Livelink New Media

A port of the OpenID Single Sign On Relying Party module to Drupal 7.

Simple module that sends emails to all moderators configured in Forum Access when new Forum Topics are posted to their Forum. There a dozen other ways to do this, but if you already configuring moderators in forum_access this makes notifying them a one step process and doesn't require several additional modules.

Once new Forum Topics are create, we used Comment Notify to allow people to subscribe to future posts to that topic.

Provides a user status color in Hex. Also it comes with support for Colorpicker.

Editable statuses, fully integrated with views.

Also it has integration with other modules through hooks.

Hooks

The module defines a set of hooks that your modules can implement in order to interact with the default behavior of User status color.

HOOK_user_status_color_load(&$status, $user)

Loads just after a user status is loaded

http://drupal.org/node/1258602 for details

Prevents other users from editing admin user, If other users has administrator user rights.

You can download the module code from here:
https://github.com/poorvab/hide_admin_account

defining user categories as entity bundles by keeping it much simpler than what "profile2" does and without depending on the "entity api" contributed module
the trick behind this module is to use $form['#entity_builders'] in user_profile_form to build the category entity on submit

categories could be defined using hook_user_categories
or managed under admin/config/people/categories where also field ui is attached

#NOD8CX: I have no plans to have a full D8 release within even a year of when Drupal 8 is released unless someone else volunteers to co-maintain that branch. This is not meant as criticism of the enormous effort others have but into D8, but an attempt to honestly inform anyone using this module of my plans. If you use this module and want to see it upgraded, open an issue asking how you can get involved and make that happen.