Enhancing Akismet with reCAPTCHA: Simple Spam Filter (0.5)

4 Comments
19 Jan

The really Simple Spam Filter plugin I wrote a couple months back has been doing a great job at blocking the really obvious spam. Since it’s release, the plugin has actually blocked about 90% of all comment spam that flows in, which is pretty good for just a couple quick anti-spam filters. The remaining 10% are easily caught by the excellent Akismet plugin. Unfortunately, Akismet still incorrectly identifies a legit comment as spam once in a while, so I still need to manually dig through the spam queue and un-spam the real comments.

So to help cut down spam even more, I updated the Simple Spam Filter to install a captcha from the reCAPTCHA web service. But instead of making everybody pass a captcha test before being allowed to comment (which I think is not very user friendly), the plugin will only display a captcha if a comment gets flagged as spam, either by one of the plugin’s anti-spam filters or by Akismet. This means that most people should never see a captcha when leaving comments. Take a look at the screenshot on the right to see this in action. If the captcha is successfully passed, then the comment is immediately posted. However, if the captcha is not passed, then the comment is immediately discarded.

So if you’re using the Akismet plugin and want to dramatically cut down comment spams even more, give the updated Simple Spam Filter a try.

Feel free to leave a comment here to let me know how it works with your blog, or if you have any suggestions :)

Posted on Saturday, Jan 19th 2008 at 11:04 pm
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4 comments

  1. # Ben Maurer Jan 20, 2008

    Hi,

    I’m one of the engineers on the reCAPTCHA team. I think this is a fantastic idea. It’d be great to see if the hooks to enable this type of filter could be merged in to the default Akismet plugin.

    - Ben

  2. # Arpit jacob Jan 21, 2008

    I get a tons of trackback spam. A solution for that would be helpful. Also not too keen on having a third party CAPTCHA service running on my blog.

  3. # Joe Tan Jan 21, 2008

    Thanks for the suggestions Arpit about trackback spam… i’m not sure if it’s possible to do some sort of verification with trackback/pings, since I dont think there’s a way to send a message back to the trackback originator…

    I had thought about having the plugin create it’s own captcha, but the reCAPTCHA service was the easiest and fastest to get up and running. Also, I want to remind you that the captcha will only display if a comment gets flagged as spam… so hopefully, most users won’t ever see it :) And since the recaptcha service actually uses an IFRAME to load and display the captcha, it won’t slow down anything on your server.

  4. # Randy Aldrich Jan 21, 2008

    I’ve had something like this on my todo list for quite a while. I’m glad someone else wrote it so I didn’t have to. I’m very glad it hooks into akismet although I wish the captcha system was just local and it didn’t depend on another system.

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