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Comments September 5, 2008

How Much Does Spam Cost? For Me, About $20,000

Filed under: Anti-spam, bbProtection, phpBB — Dave Rathbun @ 2:32 pm CommentsComments (5) 

There are multiple ways for spammers to win. The most obvious victory for them is when they manage to get content on your board or blog. But there are other victories as well that are not quite so obvious. For example, every time a spammer takes up some of my time, they’ve won a minor victory. There are plenty of studies that can be found via google that talk about how much productive time is lost to corporations due to email spam. If I look closer to home… how much of my personal time would have been lost, had I not been able to create some systems to combat spam?

How Much Is My Time Worth?

Let me start by quantifying how much I think my time is worth, based on a couple of easy metrics. When I do work in real life my billing rate is … well, I don’t want to post it, but it’s not cheap. :) I don’t think I can use that billing rate as the time value for this discussion, so let me move on. When I do work for phpBB clients, I charge between $25 and $50 an hour for the work. Yes, I am more expensive than many, but the higher rate accomplishes two things. First, it makes sure that people are serious about hiring me and not wasting my time. (There’s a theme here, see?) Second, if I can’t make at least that much working for someone else, I would rather work for myself. I have dozens of projects in various degrees of completion, and I would love to have some of them move forward. Working for someone else at $10 an hour doesn’t move my own projects forward, and I would rather work for myself for “free” that work for someone else at that lower rate.

As a result, I’m going to use $35 / hour as a nice middle-of-the-road rate for the metrics for this post.

How Much Time Is Wasted?

I will start by referencing statistics from this specific blog. Regular readers will be familiar with the process used to develop the Checkbox Challenge MOD. It was first put in place to block spam comments for this blog. Before that code was in place, I did use Akismet… in fact I continue to use it today. Unfortunately prior to the Checkbox Challenge MOD I would have hundreds of comments in my Akisment queue every single day. I never wanted to lose any legitimate content, so I would have to spend time reviewing every single comment in the quarantine list.

Let me be fairly conservative and suggest that it takes 15 seconds to process each comment. That includes reviewing it, marking it, clicking various buttons, and so on. That means every comment blocked before it gets to Akismet saves me fifteen seconds of time. How much is that worth?

Quantify the Benefit

Here are the statistics from this blog since August of 2007. As shown here, there have been a substantial number of attempted comments. :shock:

| log_month | comment_attempts |
| 2007-08   |             3567 |
| 2007-09   |             4715 |
| 2007-10   |             4643 |
| 2007-11   |             8484 |
| 2007-12   |             3977 |
| 2008-01   |             7116 |
| 2008-02   |             7979 |
| 2008-03   |             9905 |
| 2008-04   |             6245 |
| 2008-05   |             6588 |
| 2008-06   |             7480 |
| 2008-07   |             9173 |
| 2008-08   |            10791 |
| 2008-09   |              222 |

There was a total of 90,885 comments attempted. How many of them were successful? A quick check revealed that out of all of those attempts only 274 comments were successully processed. That means that 90,611 were blocked before they ever got to Akismet. If I had spent 15 seconds reviewing each of those, the total time comes out to 1359165 seconds. I can divide that number by 60 to get 22652.75 minutes, divide by 60 again to get 377.5 hours. Finally, I will multiply that number by $35 an hour and the Checkbox Challenge MOD has saved me $13,212.50.

Think about that for a minute.

Over thirteen thousand dollars in potential lost productivity due to spammer activity on this one blog. :shock:

Some might consider that 15 seconds per each comment might be too high, and that’s a valid point. I played around with the numbers before I chose that hourly rate. For example, if I reduce the number of seconds to process each comment by half and at the same time increase the hourly rate up to $50 the overall resulting cost is still a five-digit number. For that reason I will stick with these values for the rest of this blog post. I have posted the raw data so if someone wants to review the values using different input parameters they can certainly do so.

In summary:

Total comments blocked: 90,611
Total savings: $13,212.50

Adding to the Misery

Here are some numbers from other boards or blogs where I have the same code in place. All of these numbers are based on $35 / hour and 15 seconds per spam content element, whatever it might be.

Wife’s sewing blog: blocked 625 comments
My professional blog: blocked 1589 comments
Photography blog: blocked 217 comments
Other personal blog: blocked 94 comments

Total comments blocked: 2,525
Savings: $367.50
Total running savings: $13,580.00

How about web site comments? I have comment forms on two different domains and have implemented the same protection mechanism on both. Here are the numbers:

Web site comment form: blocked 11046 spam comments
Web site comment form (different domain): 251 spam comments

Total comments blocked: 11,297
Total savings: $1,648.50
Total running savings: $15,228.50

What about phpBB2 registration spammers? If they register and I have to clean them up, that’s a substantially longer process than 15 seconds. If they register and post, then that can run up the clock too. Fortunately due to my Spammer Hammer clean-up process, it’s not too bad, so I will stick with the 15 second rule for these too. Here are the numbers:

phpBB2 board #1: blocked 13,806 spam registrations
phpBB2 board #2: blocked 4,973 spam registrations
phpbb2 board #3: blocked 1,994 spam registrations
phpbb2 board #4: blocked 10,894 spam registrations
phpbb2 board #5: blocked 1,454 spam registrations

Total registrations blocked: 33,121
Total savings: $4,830
Total running savings: $20,058.50

I think I’ve made my point and will stop here. :)

True Cost of Spam

Do I really have $20,000 in the bank because of the few simple checkboxes that appear on my registration and comment forms? No, unfortunately I do not. If I can figure out how to do that, I would be ready to retire soon. :lol: The point I am trying to make is that spammers cost time even when they are not successfully posting content on your board or blog. That time has a definite value associated with it, and in my case it seems to be fairly substantial.

The numbers I used to quantify the cost of spam don’t include things like potential lost revenues from advertisers, lost member traffic, or even loss of page rank because of spam content. I will be honest; if I were still processing over a hundred Akismet quarantined comments every morning for this blog, it (this blog) would have died a long time ago. What is the cost of losing an entire site or service because of spam? That’s much harder to quantify.


The time I spend writing code has a cost. The time I spend writing blog posts has a cost. The time I spend reading other blogs or discussion boards has a cost. But these are all costs that I “opt in” to paying because they are things I want to do. I don’t have any desire to waste time processing spammer data, so that’s a cost that I want to manage or reduce. It seems that the time spent writing the Checkbox Challenge code has had a very nice return on the investment.


  1. Well, my site has no spam problem, so I just sit back and think about the spammers who waste hours of their life away. *evil grin*

    Comment by Dog Cow — September 7, 2008 @ 1:13 pm

  2. The same here, I don´t even recall the last spammer that managed to get registered on my board or send a spammy contact form.

    I get my share of spam though, entering in my abused email accounts. But well, the spam filter takes care of that pretty nicely.

    But I must admit that the numbers you give are pretty impressive, if it weren´t for the fact that you manage to block most of them it would be a true pain and impossible to deal with filtering and deleting it all one by one.

    Comment by dogs and things — September 7, 2008 @ 3:16 pm

  3. That’s essentially the point of this post. :) With the extra measures that I have in place, I am in control of my destiny, not the spammers. Getting spammer content on your board or blog is only part of the story. Anything that takes valuable time away from creating content or doing what I like to do because I have to deal with them in any form is a cost. I just found it interesting how quickly those costs added up.

    Comment by Dave Rathbun — September 8, 2008 @ 6:23 pm

  4. How many dollars did you spend summing that amount? :D

    That checkbox challenge seems an interesting alternative to captchas, but isn’t it somewhat easy to transpose it? I mean, doesn’t it only rely on the fact that is not used much?

    Comment by IceBrain — February 7, 2009 @ 12:51 pm

  5. Hi, IceBrain, and welcome. Thank you for your comment.

    Yes, one of the primary reasons the checkbox challenge is working for me is very likely to be that it’s not found elsewhere. In fact, that is one of the (selfish) reasons why I abandoned efforts to turn it into a MOD for phpBB. I am using it here on this blog, on other blogs, and on several phpBB2 boards. This post includes a summary of all of the spam registration attempts it has blocked.

    I have started brainstorming ideas for Checkbox Challenge II so I will be ready for when this version becomes less effective.

    Comment by Dave Rathbun — February 9, 2009 @ 11:26 am

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