Huda Toriq

CommentMailer is a WordPress plugin that generates and sends e-mail to your blog’s commenters to tell them that you 
have replied his/her comment on your blog’s comment system. It adds extra options on your blog’s comment form to select 
which commenters you are replying to. Submitting the reply comment will trigger the e-mail generation function thus 
send them automatically. You can customize your own notification e-mail or use the default one.

CommentMailer

Send automated email to your blog's commenters everytime you reply their comments on the blog's comment system.

codebycarter

WPBB is an easy to use forum for your WordPress site which features Facebook authentication, support for displaying your twitter account on your forum that your members can follow and so much more.
You can safely deactivate the plugin at any time and not lose a thing. The plugin will notify you if it is deactivated which you can disable by removing the page WPBB creates for you. If you decide to delete the plugin at any time, all traces of WPBB are deleted permanently.
<h4>Features</h4>
<ul>
<li>Compatibility – Fully compatible with 3.5, 3.4, 3.3, 3.2, 3.1 and 3.0</li>
<li>Ease of Integration – WPBB works with any theme, you can change your theme anytime and WPBB will automatically update itself.</li>
<li>Translatable – WPBB can easily be translated into your preferred language!</li>
<li>Facebook registration – Allow your users to register on your WordPress site via Facebook. This automatically creates a WP account for your Facebook users which they can then login to after authenticating.</li>
<li>Twitter – Enter your twitter account in your settings and your users will be able to follow your website / personal account with the click of a button.</li>
<li>Private Messaging System – Allow users to send messages to each other.</li>
<li>Member Profiles – All your WP users are automatically apart of your forum whenever you create it and have a “forum profile” which can be viewed on the forum which shows the users avatar, username, role, posts, website and signature. Signatures are apart of WPBB and allow your users to enter a signature which can be text or images and is displayed below their profile and posts.</li>
<li>Categories, Forums, Sub forums – Organise your forums into categories and your sub forums into forums. There is no limit to the amount of forums its parent can have, and each are ordered by its appearance in its parent.</li>
<li>Permissions system – Currently supports the ability to allow or disallow any role (even custom roles!) any specific permission (edit, view, read, post, reply, lock, delete, sticky). WPBB grabs all known roles from your WP site which you can set permissions for manually or copy existing permissions from a previous forum.</li>
<li>Role Permissions – New in 1.1. Allows you to choose whether a role can only edit, lock, delete and sticky their own topics or everyones.</li>
<li>Topics – If you have the permissions to do so you can edit, lock, delete, sticky, view, read, post or reply with a topic.</li>
<li>Posts – You can edit and delete any post and the posts topic affects the posts status. You can create posts in two ways, creating a topic reply with presents the WP editor for improved formatting or you can use the quick reply feature (if it is enabled in your settings).</li>
<li>Pagination System – Supports a simple pagination system which organises your topics and posts – you can set the max topics/posts per page in your wpbb settings.</li>
<li>Unread Topics – WPBB collects a list of topics which have been posted when you were offline and displays them for you. You can mark any of them as read once you’ve read them.</li>
<li>Unanswered Topics – Similar to the above feature, unanswered topics are ones which haven’t yet received any replies.</li>
<li>Admin area – The WPBB settings integrate with your existing WP admin area where you can easily manage your forums with ease. The WPBB overview allows you to change the order of a category, forum or sub forum, edit it and delete it with a single click. You can also create new categories, forums, sub forums and topics via the admin area.</li>
<li>Settings – WPBB is jam packed with settings that you can use to customise the forum any way you want to.</li>
<li>Tools – Tools help make your life easier. Tools such as updating your roles whenever you add, change or remove them and a tool to recreate the forum page if you ever accidentally delete it.</li>
</ul>
And much much more!

WP Bulletin Board

WP Bulletin Board (WPBB) is an easy to use forum for your Wordpress site with Facebook and Twitter features.

CommentMailer vs WP Bulletin Board