Brandon Fenning

Since the vast majority of WordPress spam is automated in nature, the goal of BotBlocker is to block comment spam bots and not hinder users. This is accomplished through the use of honeypot technology, which tricks the spambot into identifying itself by performing actions that a human could not.
BotBlocker’s features include:
<ol>
<li>Works out of the box to block spam</li>
<li>Automatically stops spam-bots from commenting</li>
<li>Zero hindrance to users: no CAPTCHAS, math questions, passwords or extra input required</li>
<li>Zero false positives and ignores registered users</li>
<li>Can be configured to completely block spam-bots or flag comments as spam</li>
<li>Spam detection messages can be easily adjusted</li>
<li>No javascript or cookies required</li>
<li>Hooks into <code>wp-comments-post.php</code> to prevent spam-bots from directly submitting spam comments</li>
<li>Should work fine with most customized comment forms</li>
<li>No API keys required</li>
</ol>
http://www.lform.com/botblocker/ for more information.
Plugin by <a href="http://www.lform.com/" rel="nofollow ugc">LFORM, a web design company</a> in New Jersey.

BotBlocker

Kills spam-bots, leaves humans standing. No CAPTCHAS, no math questions, no passwords, just spam blocking that stops spam-bots dead in their tracks.

Paolo Melchiorre

Add a contact form to any post or page by inserting <code>[contact-form]</code> in the post. Messages will be sent to the post’s author or any email address you choose.
Or add a contact form to a text widget. Messages will be sent to the email address set in your Settings -> General admin panel or any email address you choose.
Your email address is never shown, and the sender never learns it (unless you reply to the email).
As seen on WordPress.com.
This plugin was imported from <a href="https://wordpress.org/extend/plugins/grunion-contact-form/" title="Grunion Contact Form - wordpress.org" rel="ugc">Grunion Contact Form</a> but it adds full internationalization using localized string from WordPress core.
An e-mail <a href="http://en.wikipedia.org/wiki/Signature_block" title="Signature block - Wikipedia" rel="nofollow ugc">signature block</a> was appended to the end of the e-mail message containing the sender’s name, email address, website and IP and delimited from the body of the message by a single line consisting of exactly two hyphens, followed by a space, followed by the end of line (“– \n”). This <a href="http://tools.ietf.org/html/rfc3676#section-4.3" title="Usenet Signature Convention - RFC3676 - IETF" rel="nofollow ugc">signature cut line</a> allows software to automatically mark or remove the sig block.
<h4>Configuration</h4>
The <code>[contact-form]</code> shortcode has the following parameters:
<ul>
<li>
<code>to</code>: A comma separated list of email addresses to which the messages will be sent. 
If you leave this blank: contact forms in posts and pages will send messages to the post or page’s author; and 
contact forms in text widgets will send messages to the email address set in Settings -> General.
Example: <code>[contact-form to="you@me.com"]</code>
Example: <code>[contact-form to="you@me.com,me@you.com,us@them.com"]</code>
</li>
<li>
<code>subject</code>: The e-mail subject of the message defaults to <code>[{Blog Title}] {Sidebar}</code> for text widgets 
and <code>[{Blog Title}] {Post Title}</code> for posts and pages. Set your own default with the subject option.
Example: <code>[contact-form subject="My Contact Form"]</code>
</li>
<li>
<code>show_subject</code>: You can allow the user to edit the subject by showing a new field on the form. The 
field will be populated with the default subject or the subject you have set with the previous option.
Example: <code>[contact-form subject="My Contact Form" show_subject="yes"]</code>
</li>
</ul>
<h3>License</h3>
<h4>Send E-mail</h4>
Copyright (C) 2011 Paolo Melchiorre
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program. If not, see <a href="http://www.gnu.org/licenses/" title="Licenses - GNU Projec" rel="nofollow ugc">Licenses – GNU Project</a>.
<h3>Donation</h3>
This plugin is free for everyone! Since it’s released under the GPL License, you can use it free of charge on your personal or commercial blog. But if you enjoy this plugin, you can thank me and leave a <a href="https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=10617157" title="Donate with PayPal" rel="nofollow ugc">small donation</a> for the time I’ve spent writing and supporting this plugin.

Send E-mail

Add a contact form to any post, page or text widget. Messages will be sent to any email address you choose. As seen on wordpress.com with added i18n.

BotBlocker vs Send E-mail