DjZoNe

More than that, it checks if all fields filled correctly, and also makes sure to avoid comment duplication, and has flood protection capabilities as well.
Probably one of the best ways you could spice up your WordPress Blog with AJAX; readers love it! Must see for yourself.
This plugin works well in all major Web browsers, and uses discrete AJAX. 
That means if JavaScript disabled, it’s using the original comment posting method.
Ajax Comments known to work well, with Authimage plugin, but I rather suggest Akismet, as it is free for personal use.
Features:
<pre><code>* comment form validation happens server-side without refreshing or leaving the page
* Script.aculo.us Fade In/Out Effects make readers happy
* works with AuthImage captcha word verification plug-in to prevent comment spam
* still works traditionally if browsers don't support JavaScript (or have it disabled)
* uses existing theme code to match styled comment threads when producing new comments
* 25-second server timeout ensures readers aren't left hanging
* works in current versions of Firefox, Internet Explorer, Opera, Netscape, and Safari.
</code></pre>
Recommendations:
<pre><code>* perfectly compliments any well-styled comment form design-don't design without it
* best when moderation is off (seems more real-time) and AuthImage is installed (self-moderation is the best moderation)
</code></pre>
<h3>Known bug</h3>
I’ve discovered that AJAX Comments 2.0 stops working properly if you 
have ShowOnFrontPage plugin (v0.3.1) installed.
And we got another report, that it also stops, when you have SpamKarma activated.
We are working on a solution.
<h3>AuthImage Integration</h3>
<ol>
<li>Open ajax-comments.php and uncomment lines: 92, 152, 153.</li>
<li>
Open comments.php from your /themes directory and use the following code (mostly just the ids) for AuthImage to appear in your comments form:
<pre><code> <?php if ( !$user_ID ) : ?>

 <img id="auth-image" src="<?php echo get_option('siteurl'); ?>/wp-content/plugins/authimage/authimage-inc/image.veriword.php" alt="Verification Image" />
 <label for="code">Word Verification (<a href="#" onclick="document.getElementById('auth-image').src+='?'+Math.random();return false" title="Generate another Captcha Word Verification image.">can't read it? try another!</a>)</label>
 Please type the letters you see in the picture.
 <input name="code" id="code" type="text" class="text" tabindex="5" />

 <?php endif; ?>
</code></pre>
</li>
</ol>

AJAX Comments

Post comments quickly without leaving or refreshing the page.

Gungor Budak

Shouty (shoutbox) is a WordPress plugin for you to receive messages from your users. It creates a custom post type called “shout” which will allow you to administer shouts from the Dashboard as you do for the default post types. You can add Shouty in a post, page or a widget using its shortcode. The shortcode has certain options for you to customize the look and function of the Shouty. Shouty also creates a custom category option which can be used to create multiple shoutboxes on your website. To do that, you should first create a category, then set it in the shortcode. Shouty shares messages using AJAX and protects your blog using Honeypot spam protection technique. Users must log in to share shouts. It doesn’t accept any HTML but http and https links are converted to <code><a></code> tags when the shout is shared. You don’t have to worry about unclickable links.
How to use Shouty
Insert the shortcode below into any post/page or widget.
<pre><code>[shouty category="home-page" look="widget" user="hide" form="hide" messages_number="5" messages_title="hide" messages_users_avatar_size="60" show_more_button="hide"]
</code></pre>
Options you can set for the shortcode
<ul>
<li>category (category-slug; default: empty; Limits shout viewing and posting to a previously created shout category)</li>
<li>look (post | widget; default: post; Switches looks – widget look is more compact)</li>
<li>user (show | hide; default: show; Displays user information at the top of the form)</li>
<li>user_avatar_size (in px; default: 64; Changes size of the user avatar in user information)</li>
<li>form (show | hide; default: show; Displays Shouty form and the share button)</li>
<li>messages_title (show | hide; default: show; Displays a title at the tops of the shouts)</li>
<li>messages (show | hide; default: show; Displays shouts)</li>
<li>messages_links (show | hide; default: show; Displays URLs in the shout)</li>
<li>messages_number (a number; default: 10; The number of shouts to be viewed in one time)</li>
<li>messages_users_avatar_size (in px; default: 32; Changes size of the user avatar on the left of the each shout)</li>
<li>share_links (show | hide; default: show; Displays Facebook share and Twitter tweet links)</li>
<li>show_more_button (show | hide; default: show; Displays show more button at the end of the shouts)</li>
</ul>
The plugin is written in English and has been translated into Turkish by <a href="http:/www.gungorbudak.com/" title="Güngör Budak" rel="nofollow ugc">myself</a> 
. German (by <a href="http://www.jordin.eu/" title="Pascal Jordin" rel="nofollow ugc">Pascal Jordin</a>), Serbian (by <a href="http://firstsiteguide.com/" title="First Site Guide" rel="nofollow ugc">Ogi Djuraskovic</a>) and Spanish (by <a href="http://www.webhostinghub.com/" title="WebHostingHub" rel="nofollow ugc">Andrew Kurtis</a>) translations are also available. You’re welcomed if you want to translate it into your language. Use translations.pot, rename it as shouty-LANGCODE.po (e.g. shouty-tr_TR) and open it in Poedit. Translate and save. There should be a MO file created by Poedit. Send PO and MO files to me, then I will add them in the next release.

Shouty

Nice plugin, just what I was looking for.



Nice plugin

Shouty is a shoutbox powered by AJAX that you can add anywhere using shortcode which comes with some options to customize Shouty.

AJAX Comments vs Shouty