Two Four-Letter Words: Spam and Free

Spam is, for many of us, the worst aspect of Web 2.0. The threat of spam of course creates an need, and hence an opportunity, for spam-fighting services. Last week, I compared four of them: Akismet, Defensio, Mollom, and TypePad AntiSpam. The comparison was prompted by the launch of the last of these (the list, like the comparison table in the previous post, is in order of launch date).

TPAS is interesting, not just because it is the most recent, but because it has claims to be the most free. I use the plural claims because TPAS seems to make that claim with respect to each sense of the word free: free of charge (gratis) and free (libre, open source) software.

In this post, I’ll extend the comparison between the four services with respect to each sense of free. First, free of charge. The last two lines of the comparison table refer to this kind of free. The first of these lines shows that each of the four services is free for personal use.

The last line of the table asks whether each service is free for commercial use. It answers “Yes” for TPAS, and “No” for each of the other services. Following some email exchanges and some thinking, it seems that the pricing issue needs clarification.

Akismet has multiple levels of commercial API key. For example, a problogger key is $5/month. Given that a problogger is defined for this purpose as one who makes more than $500/month, the cost seems reasonable (but then, I’m not a problogger). That an enterprise key starts at $50/month also seems reasonable (but then, I’m not an enterprise).

Defensio is free for commercial use up to a limited amount of traffic. That’s a paraphrase of an email. is down at the moment. I don’t know whether that means that the service is down.

Mollom currently describes its future pricing model as follows.

The basic Mollom service will be free… but it will be limited in volume and features… Our goal is to make sure that the free version of Mollom goes well beyond meeting the needs of the average site…

For large and mission-critical business and enterprise websites, we will offer commercial subscriptions. We are currently working out our commercial pricing scheme for access to more advanced features, unlimited traffic, enhanced performance, reliability and support.

TPAS, per its FAQ, “is free, and will always be free, regardless of the number of comments your blog receives.” The FAQ also addresses how Six Apart will support the service; the firm “may choose to provide enterprise-class services on top of TypePad AntiSpam at some point in the future.”

TPAS is the outlier on this “free as in beer” issue, but I now think that it’s closer to the others than I first thought and implied. Like the other three, it seeks to make money from enterprise clients (and I don’t see anything wrong with that). The difference is that it doesn’t attach the price tag to AntiSpam itself.

TPAS is also the outlier on the free software, or “free as in freedom,” issue. As I remarked in the earlier post, “while the TPAS inference engine is open, the rules are hidden.”

I wouldn’t be at all surprised to see Akismet, Mollom, or both move to a similar model. I base this on the following assumptions.

  1. Spam-fighting software has the classic intelligent system split between inference engine and rules base. In particular, Akismet and Mollom already have this architecture.
  2. The action is in the rules, which are specific to the domain of spam-fighting.
  3. Following from the above, you don’t give much away to spammers or to competitors if you free/open-source your engine.
  4. The people behind Akismet and Mollom don’t want to cede the “free high ground” to TPAS.

With respect to this aspect of free (libre), as with respect to the first aspect (gratis), I may have exaggerated TPAS’ outlier status. TPAS does have a legitimate claim to being more free than its competitors in each of the two senses of free. But the gap between TPAS and, say, Akismet, may not be as great or as durable as might at first appear.

That conclusion is, of course, my opinion. Comments (or email: andrew at changingway etc.) would be a good way of telling me that you draw a different conclusion or that my conclusion is based on faulty premises or reasoning. I’d welcome other relevant comments. For example, you might know of a spam-fighting service other than the four I’ve focused on.

AntiSpam: TypePad and the Trio

There’s a new spam fighting service in town: TypePad AntiSpam. To put it another way, the spam sheriff of TypePad town is now available to lay down the law elsewhere.

TPAS competes directly with Akismet. The table compares the two spamfighting services with each other, and with two other competitors. I’ve ordered the columns from earliest to most recent (so the alphabetical order is coincidental).

Akismet Defensio Mollom TypePad AntiSpam
Previous post at Changing Way? Yes Yes Yes No
Service offered by Automattic Karabunga Mollom: shares founder with Acquia Six Apart
If in doubt, challenge with CAPTCHA? No No Yes No
Service has own API? Yes Yes Yes No, uses Akismet API
Open source engine? No No No Yes
Free of charge for personal use? Yes Yes Yes Yes
Free for commercial use?* No No No Yes

Each of the four is the odd one out in at least one sense. Akismet was first out, and remains the service against which each rival positions itself.

Defensio is the one that doesn’t share developers or an organization with a prominent publishing or content management platform (Akismet/WordPress, Mollom/Drupal, TPAS/TypePad and Movable Type).

Mollom uses CAPTCHA when unsure whether a comment is ham (the good stuff) or spam, whereas each of the others queues the suspect comment for moderation. That’s something of an oversimplification about the others: for example, a TPAS client can use CAPTCHA when told about a suspect comment by the server.

TPAS is open source (GPL V2). I found this particularly interesting, given that the other three are not. They explain that source code access would help spammers. I then realized that while the TPAS inference engine is open, the rules are hidden.

TechCrunch is currently using TPAS via the WordPress plugin that Six Apart provide. Mike Arrington reports that TPAS is doing well so far.

Anil Dash wrote the announcement post at the Six Apart blog. TPAS also has its own blog.

Missing from the table are two of the most interesting potential comparisons: performance and market share. I suspect that we will before long see data relevant to these comparisons, and challenges to the data, and…

Update, after a few hours sleep and some further research. I made a few changes to the above.

I’d like to add that I find the name TypePad AntiSpam interesting. Or rather, I find the choice of name interesting. The name may give the impression that it’s more specific to TypePad than it really is. My guess is that Six Apart think they have a winner on their hands here, and that the success of TPAS will raise awareness and reputation for TypePad.

* Final update to this post. I decided that the last line of the table, while close to the mark, needs clarification. Hence the followup post (see the first comment to the current post).

Defensio Against Comment Spam

logoDefensio is a spam comment blocker. Defensio boasts a few features lacking in Akismet, most notably the ability to sort your blog’s blocked comments by “spamminess”, according to Mark Hendrickson at TechCrunch. That got me interested enough to try the Defensio plugin at my WordPress test blog, but then realized that WordPlay doesn’t get enough spam comment to provide a test of Defensio.

Mark refered to “a few features lacking in Akismet,” and goes on to imply Defensio’s “open API that makes the blocker available for use with non-blogging applications” is one of them. But that feature is present in Akismet, and clearly described in the FAQ: The Akismet API can be adapted for almost any application with submitted content, including forums, wikis, and contact forms.