user 

Author: Marco Cimmino Import and export users from/to CSV files, supports all WordPress profile data also Cimy User Extra Fields plug-in
Installation:
Just copy the plug-in in your plug-in directory and activate it
faq:
I have a lot of questions and I want support where can I go? http://www.marcocimmino.net/cimy-wordpress-plugins/cimy-user-manager/faq-and-comments/

Authors: DeannaS, kgraeme When users are first created, they are automatically assigned to the primary blog. But, you may want to set them up on multiple blogs by default. This is especially helpful if youre using bbpress or other forum software where the user needs a role on that blog in order to participate. This plugin allows site admins to set the default role on as many blogs as desired for all new users
Installation:
Place the cets_default_user_role.php file and the cets_default_user_role folder in the wp-content/mu-plugins folder. Go to Site Admin - New User Default Role to activate the plugin and set default roles.

Author: Jerod Santo With this plugin, a WordPress site Administrator can set some default options for new user accounts. All new users registered on the system will inherit these settings. The following user defaults can be set
Installation:
Upload wp-user-defaults.php to the /wp-content/plugins/ directory Activate the plugin through the Plugins menu in WordPress Configure default user settings via the new "Default Settings" page in the "Users" menu

Author: Morten Proschowsky Change User lets the administrators of a blog log in as any user of the blog
Installation:
Upload change-user.php to the /wp-content/plugins/ directory Activate the plugin through the Plugins menu in WordPress There are no settings for the plugin. The plugin is only tested on Wordpress 2.8.0 and newer, but might work on older versions.

Author: Sulaeman User Link Feed enables user blog to contribute link feeds
Installation:
Download the zip file, unzip it, and copy the "user-link-feed" folder to your plugins directory. Then activate it from your plugin panel. After successful activation, User Link Feed will appear under your "Settings" tab. Note that User Link Feed requires WordPress 2.5 or higher.
faq:
Before you can use User Link Feed, you need to fill out its Settings form. First, you will need a reCAPTCHA API key. If you are already using the WP-reCAPTCHA comments plugin, then you dont need another key (youll see the form is pre-filled with your existing key). If youre not using WP-reCAPTCHA, then follow the link on the Settings form to get a key. Then the only other requirement is that you provide the email address where youd like the form submissions to go. All the other settings include comments explaining what they do. Putting User Link Feed on a page ? Just put the shortcode tag: [userlinkfeed] Putting User Link Feed Form on a page ? Just put the shortcode tag: [userlinkfeedform] on a page, and thats where the User Link Feed will appear. Thats all

Author: Reza Moallemi the Advanced User Agent Displayer plugin displays the Browser and the operating system of people who commnet on your blog. Currently Support for Desktop and moblie operationg systems and browsers. Browsers: Internet Explorer, Opera, Firefox, Safari, Chrome, Epiphany, Avant, Maxthon, Konqueror and ... Platform: Windows(2000, XP, Vista, 7), Linux, Mac, iPhone and ..
Installation:
Upload advanced-user-agent-displayer to the /wp-content/plugins/ directory Activate the plugin through the Plugins menu in WordPress

Author: Simon Wheatley Extends the User Photo plugin to allow the generation of square thumbnails. You MUST have the User Photo plugin installed, or this plugin will NOT work
Installation:
The plugin is simple to install: Download square-thumbnails-for-user-photo.zip Unzip Upload square-thumbnails-for-user-photo directory to your /wp-content/plugins directory Go to the plugin management page and enable the plugin Give yourself a pat on the back

Author: Vincent Prat WordPress does not allow your users to communicate with each other. Some forum plugins can add this functionnality but are quite heavy, do other things and updates might not be focussed on improving the messaging features. This is why User Messages is born: a plugin to facilitate communication between your users