jammycakes

This plugin rejects outright any comments that contain either (a) BBCode 
[url=…] tags or (b) more than a predefined number of hyperlinks. As comments 
of this nature are almost exclusively spam, this should cut down drastically on 
the amount of detritus that Akismet has to deal with, making it easier to check 
for false positives in your spam queue.
<h3>Configuration</h3>
The default settings enforce a limit of two hyperlinks per comment. 
To change this, edit the number in the line just below the copyright notice 
which says:
<pre><code>define('MAX_HYPERLINKS', 2);
</code></pre>
If you set it to zero, it will not allow any hyperlinks. To allow unlimited 
hyperlinks and only block BBCode, comment out this line.
<h3>Redistribution</h3>
Copyright (c) 2007 James McKay 
http://www.jamesmckay.net/
Permission is hereby granted, free of charge, to any person obtaining a copy 
of this software and associated documentation files (the “Software”), to deal 
in the Software without restriction, including without limitation the rights 
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
copies of the Software, and to permit persons to whom the Software is 
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in 
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 
SOFTWARE.
<h3>Reporting bugs</h3>
When reporting bugs, please provide me with the following information:
<ol>
<li>Which version of Comment Timeout you are using;</li>
<li>Which version of WordPress you are using;</li>
<li>The URL of your blog;</li>
<li>Which platform (Windows/IIS/PHP or Linux/Apache/MySQL/PHP) your server 
is running, and which versions of Apache and PHP you are using, if you 
know them;</li>
<li>The steps that need to be taken to reproduce the bug;</li>
<li>If possible, any relevant information on other plugins or configuration 
options that you may think appropriate.</li>
</ol>
See the following blog entry for further guidance on troubleshooting and 
reporting problems:
http://www.jamesmckay.net/2007/04/how-to-report-issues-with-wordpress-plugins/
<h3>For more information</h3>
For more information, please visit the plugin’s home page:
http://www.jamesmckay.net/code/link-limits/
The Mercurial repository and issue tracker for this plugin are at:
http://bitbucket.org/jammycakes/link-limits/

Link Limits

Rejects comments that contain BBCode or too many hyperlinks.

SzMake

In English:
No spam in comments. blocked by Invisible internal token-code with ajax.
This plugin blocks 100% of spam messages in the author of the environment.
It blocks spam without using the CAPTCHA input-field.
There is no modification of display the comment form.
(but the commnet which is posted by spammers manually via browser is not blocked by this plugin)
In Japanese:
このプラグインはコメント投稿時にAjaxを使ってスパムロボットによる投稿コメントか判別し自動でブロックするプラグインです。
作者の環境では、今のところこのプラグインで100％スパムBOT投稿がブロックできています。
一般的なスパム対策としてAkismetプラグインがありますがブロックされるのは９割程度で100%は止まりませんでした。
別の方法としてCAPTCHA系のプラグインを使いBot対策する手段もありますが、こちらはほぼ100%スパムBotからの投稿はブロックされますがユーザーに煩わしい確認文字入力に毎回協力してもらう必要がありました。 このプラグインでは、見えない入力欄を用意してコメント投稿時にjavascriptでCAPTCHA入力に変わる固有の確認トークン入力処理をで行うことでスパムBotからの投稿をブロックします。
利用ユーザーのコメントフォームの見え方は変わりません。
(残念ながらこのプラグインではブラウザを介した手入力によるスパム投稿はブロックできません)
<a href="http://wp.szmake.net/sz-comment-filtter/" title="Documentation in Japanese" rel="nofollow ugc">日本語の詳細説明ページはこちら</a>
<h4>Translators</h4>
<ul>
<li>Japanese (ja)</li>
</ul>
<h3>Contact</h3>
email to contact[at]szmake.net 
twitter @sxmtz

Sz Comment Filter

No spam in comments. blocked by Invisible internal token-code with ajax.This is not used CAPTCHA.

Link Limits vs Sz Comment Filter