The Quest For Best Spam Blocker Software Continues

Sep 25, 2009   //   by Hackadelic   //   WordPress  //  12 Comments
This entry is part of a series, The Spam Chronicles»

Spam, Now with Real Bacon!Some time ago I installed spam blocker software to help me manage the tons of spam I’ve been getting. Meanwhile, I have revised my choice of spam blocker, tried another one, and I’m giving up that one, too. Here is the story…

Incapable Invisible Defender

My first spam blocker of choice was Invisible Defender. It probably isn’t the best spam blocker out there, but it sure was (and probably still is) the simplest of the anti-spam plugins I found, while it seemed to do a reasonably good job in blocking spam. It did not block all spam, but enough to make reviewing the spam queue a feasible task again.

However, the amount of spam attacks continuously increased over time, and with it the amount of “false negatives”, until at some point it became beyond all bearing to manage them by hand. So I revived my quest for a spam blocker utility again.

An Overeager NoSpamNX

NoSpamNX was another anti-spam blocker that looked very promising at first. Regarding simplicity very close to Invisible Defender (code fingerprint of 20K against Defender’s 12K), NoSpamNX seemed to do a much better job. After I installed and activated it, the amount of spam in my spam queue dropped to zero! I was delighted!

My delight was put to an end by an increasing number of emails by users reporting to me NoSpamNX had rejected their regular comment. What?!?

Here is what the NoSpamNX plugin author says about false positives:

Due to the functionality of NoSpamNX false-positives are nearly impossible.

Impossible my ass! :roll:

With a spam blocker, false positives are particularly infuriating, because there is no way to know about them. A blocked comment is a gone comment. While this is welcome with real spam, it is intolerable otherwise! I’m don’t want to think about how many prospective commenters has left frustrated without bothering to leave me a message.

Needless to say: NoSpamNX is history here! πŸ‘Ώ


The most downloaded and most rated anti-spam plugin for WordPress is WP-SpamFree Anti-Spam. Alas, it is also the most bloated one (WP-SpamFree’s code fingerprint is nearly 400 KBytes, compared to about 20K of NoSpamNX, or roughly 12K of Invisible Defender). Before I resort to such a bloated solution, I’d like to know that leaner spam blocker software won’t do it. Unfortunately, the list of leaner plugins gets pretty short.

Regardless, I’m adding one important criterion to my spam blocker software requirements:

Zero false positives!

Still the question remains: Mirror, mirror on the wall, who is the best spam blocker of all?

The quest continues…


  • well, to add to the discussion I have tried akismet, defensio, typepad, SK2, bad behaviour and monty.

    I am still stuck with monty: (the wpmu version) but the single wordpress version is still in beta.

    Its basically a bayesian based system running on your own system that is why I prefer it to any other external solutions…

    • Ovidiu, what’s your experience with MontySpam? Any false positives or negatives?

  • Ah.. I found it using the series… you have written your own which is working. πŸ™‚ Look forward to hearing more.

  • Hi Hack, I’m unclear which anti-spam tool you’re using at the moment with great success.
    Secondly, I’m using WP-SpamFree. I note is does have a large code fingerprint, but my understanding (from looking at a page load analysis) is it does not load all that into the reader’s browser, it is back-end code; have you found to the contrary, or is your objection to its code size out of principle?

  • If having zero false positives is important to you, don’t use SpamFree! I’ve been active on a WordPress site that uses it, and it’s like pulling teeth to get any comments through; virtually anything I try to post gets falsely blocked as spam…

  • so what anti spam software are you using right now?

    • I’m using my own hack, and it works like a charm. πŸ™‚

  • Looks like you’re using what I recommended!

    We’ve had zero spam as well! πŸ™‚

    • Ray, true, your comment gave me ideas! Thanks! πŸ™‚

  • The problem with Invisible Defender is it became too popular!
    I also noticed that spam was leaking in even with Invisible Defender.

    I’ve found that a modified version of Invisible Defender v1.2 is the best technique (so far).

    Why am I using v1.2? No admin options page. That equals more kbs! I’m using a solution that is now only 5kb!

    What I changed were the input names and values, as well as a couple of attributes, namely the CSS, since intelligent spam bots can detect if a field is hidden or not.

    • Ray, I did some hacks myself, I’ll see how they work out… πŸ˜‰

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