Deciding on the best method of spam prevention on your blogs, forums, or even contact forms can be difficult. In this article we will take a look at a service called Akismet and how it can help. We will also look at why some other methods of fighting spam fail.

They give a few ways to waylay the spammers including:

• Disallowing multiple consecutive submissions
• Keyword Blacklist
• CAPTCHA
• and a service called Akismet

They go into a bit more detail on this last one, even going so far as to included code (this class) and examples of how to let the Akismet service see if something is spam or not. Links to libraries for other languages are included too.

I'm celebrating [the death of PHP4] with the second release candidate of Zend Framework 1.6.0, which should drop today. There are a ton of new features available that I'm really excited about. I'm not going to go into implementation details here, but instead catalogue some of the larger and more interesting changes that are part of the release.

He mentions the Dojo integration, updates to the unit testing infrastructure, captcha support in the Zend_Form component, Firebug support and included pagination functionality. You can grab this preview release from the downloads page on the Zend Framework website.

From the company's description:

Securimage is an open-source free PHP CAPTCHA script for generating complex images and CAPTCHA codes to protect forms from spam and abuse. It can be easily added into existing forms on your website to provide protection from spam bots. It can run on most any webserver as long as you have PHP installed, and GD support within PHP.

Features of the tool include simple addition and validation methods, the ability to make audible CAPTCHAs and True Type font support. You can download the software from the project's website.

In this last article of the series I'm going to show you how to couple this class with a simple randomizer mechanism to implement a basic yet effective application that will be capable of outputting on the browser different random strings, which will be previously embedded into a predefined image stream.

They start with their previous version of the class and work off of it, extending its functionality to add a multi-call ability and to hook into a RandomGenerator class to create the string.

The latest plugin uses my PHP/JS randomisation techniques to create a key and protect against spam. I've took this bold move to see what affect it has and if the blog spammers will get round it because it no longer uses javascript cookies.

His plugin includes features including a lack of cookie use, delay on spammers (slows spam scripts) and doesn't use CAPTCHAs. You can also check out this section on Gareth's blog for the latest on the plugin.

Commonly CAPTCHA is a visual image where the user is asked to type the word they see (or hear) however some provide a logic puzzle [...] Re-captcha works by asking the user for two words instead of the normal one, one word is known to the system and is the actual CAPTCHA the second is an unknown word, if the user gets the CAPTCHA then the users "guess" for the unknown word is recorded, over time a word is given a probability score and when high enough becomes a known word.

They Also include links to re-captcha modules for two of the popular CMS/blogging tools - WordPress and Drupal - to make integration easy.

For the past few days with the help of Greg Beaver (CelloG), I have been implementing user notes in the pear user documentation. This is now live and running using text-captcha-numeral and an administration backend where any developer can approve comments.

[...] Anyways, this is currently working, you have to go on a package's documentation link and then click on end-user documentation. You will then notice at the bottom a link that says "Add a note/comment".

He's also looking at adding some Javascript functionality to make it a bit more "pretty" (some jQuery features like popups/fading/etc). You can see an example of it already on the MDB2 documentation page.

Although you might not know it by the name, a captcha is one of those little boxes you see, more and more lately, that ask you to type in a random code to verify that you are a human being and not a robot. There are many different varieties, but the basic idea is an image that is obscured slightly but readable by a human and used as a passcode for secure entry to a system or task.

The method is a simple combination of random text, a custom image, some of the PHP graphics functions, and a little addition to your HTML form (and PHP session) to get things up and running.

I recently updated My Two Cents. My Two Cents (or MTC) is a simple PHP class to add comments to any PHP driven site. It is was written with simplicity in mind but still has some strong features and is easily tweakable. It consists of a single PHP file and can be added with just a few lines of code.

The post also describes some of the functionality it comes with, including a CAPTCHA mechanism and a blacklist feature to help reduce spam. There's also a bit of multi-language support included as well.

"ModernCaptcha" is a simple script in order to prevent spam in a very user friendly way. In a few words, your visitors don't have to type some characters as you see on the most websites, the verification is made by choosing the company name belonging to the logo that is show.

It's an interesting approach, but, as one reader pointed out, bots has a one in five chance of guessing correctly. That's way less than with a more standard image manipulation CAPTCHA method. I'm not sure I'd want to use it on my sites, but it might be good for a smaller site.

There's a demo of the end result and a download of the latest version as well as some limited support provided in the comments of the post.