Blog Tips: CAPTCHA and comment spam

We’re always told as bloggers that a key way to build our audience and connect with other bloggers is to comment on other people’s blogs. This is all well and good, and I try to leave at least as many comments on other blogs as I receive on my own, but there’s one thing that drastically decreases the chance that I will leave a comment on someone’s blog – CAPTCHA! This post focuses on what CAPTCHA is, and why you shouldn’t be using it on your blog.

(NB: the contents of this post are just my opinion! I know there are a lot of people who agree that CAPTCHA should not be used, but presumably there are also some people who aren’t bothered by it, otherwise no-one would use it. Read on and see which side you fall on!)


This is a ‘beginner’ blogging tip, aimed at those who have just started to blog, and are trying to decide how to set up their site.

What is CAPTCHA and why do people use it?

CAPTCHA stands for ‘Completely Automated Public Turing test to tell Computers and Humans Apart’. This is CAPTCHA:

CAPTCHA and comment spam

It’s that box that pops up sometimes when you’re trying to leave a comment on someone’s blog, asking you to copy the numbers or words that you can see in the box.

The reason that some bloggers have CAPTCHA installed on their blog is because it reduces the number of spam comments that they receive. Sometimes non-human ‘bots’ automatically leave spam comments on blogs – it’s something that all bloggers have to deal with. Since these robots don’t have eyes like humans do, they can’t read the CAPTCHA code, and therefore it stops them leaving a spammy comment on that particular blog.

The reason that these bots want to leave their spammy comment on your blog is because they want to gain a link back to their own spammy website (remember when we talked about getting an SEO boost from linkbacks?).

Spam comments can take lots of different forms. Here are a few that I have in my spam folder right now:

“You’ve made some really good points there. I looked on the internet for more info about the issue and found most individuals will go along with your views on this website.”

Seems innocent enough, no? Perhaps it would make sense if it was on a Blog Tips Tuesday post, but this spam comment was posted on a recipe post, so it caught my eye as being a bit out of place. Plus the website that the person/bot had linked back to seemed really spammy, so into the trash it goes.

“Free Webmaster Guide. I get read your own article. It’s extremely helpful. We will benefit a great deal from the item. Fluent.”

Spam comments are often written in really terrible English! I have no idea what they were trying to say with that random ‘fluent’ at the end but whatever it was, it didn’t work. The ‘free webmaster guide’ part was a link back to their page, as expected.

“Now we can play jeux de Mario moto, with lots of new friends and enemies, as well as cool new features. When all is said and done, learning how to cook has never been easier. Adventures and mazes etc stimulate the mind to think and find solutions.”

Of course, this was then followed by a whole load of links. I don’t even know why they bother.

So should I use CAPTCHA on my blog?

In a word: no.

Considering how irritating these spam comments are, why is CAPTCHA such a bad thing? Well, because as well as reducing spam comments, CAPTCHA reduces useful comments as well.

You’re meant to be encouraging someone to leave a comment on your blog, not making it harder for them. If I’ve spent time writing out a lovely comment for you, why should I then spend another minute copying a hard-to-read list of numbers into a box? Most of the time I’ll do it, but the chances of me leaving another comment on that blog in the future is very slim.

That might sound petty, because when it works properly, filling in a CAPTCHA code only takes about ten seconds or so. But, that’s the thing: when it works properly. Firstly, the code is deliberately difficult to read (so that non-human bots can’t somehow read it automatically) – so the chance of making a mistake and needing to do it a second, or even third, time isn’t that slim. But I’ve also found that sometimes, even when the correct code is entered, it still rejects it – and I’m certain that the correct code has been entered, that’s not just me having bad eyesight!

In fact, on occasion I’ve even discarded a comment that I’ve already written because I simply can’t be bothered making five attempts at writing a silly code into a silly box. It just seems pointless.

How can I stop spam comments if I can’t use CAPTCHA?

There are several other ways to avoid publishing spam comments on your blog:

Comment moderation

The simplest way is to turn on comment moderation. This means that you will have to read any comment that comes in, and decide whether or not you want to publish it on your blog.

Pros: If you read each comment thoroughly, you should have a 100% success rate, and no spam comments will end up on your blog. I also find the spam comments pretty entertaining, so this method means you get to see them all.

Cons: If you get more than, say, ten comments a day (including spam, which can be a lot!), this is quickly going to become a bit of a chore.


Arguably the most popular WordPress plugin to use to combat comment spam is Akismet. This is what I currently use. Akismet automatically filters spam comments into a separate folder, and they never get published on your blog. It’s worth occasionally checking through this folder and emptying it if you’re sure it only contains spam.

Pros: Everything is done automatically, so it doesn’t take up any more of your time. It also tends to be pretty accurate at determining whether a comment is spam or not.

ConsOccasionally, a real comment will be flagged as spam for whatever reason. This is very rare, but it explains why it’s worth giving your spam folder a glance once in a while.

Here are my Akismet stats:

Akismet accuracy rate

As you can see, a few comments slipped through the net, but considering it caught nearly 30,000 spam comments, with a 99.82% accuracy rate, I’d say it’s pretty good overall.


Another WordPress plugin that combats spam comments is GrowMap. This plugin adds a small checkbox under your comment form, that says ‘confirm that you are not a spammer’. The commenter just needs to check the box to show that they’re a real person. I don’t personally use this plugin, but I think it’s a good option – it’s nowhere near as much of a burden to the commenter as CAPTCHA is, and it’s unlikely to put anyone off commenting.

It looks a bit like this:

GrowMap comment spam plugin

Pros: Easy to use, not too much of a burden to the commenter.

Cons: You don’t get to read all the ridiculous spam comments you get sent! (may or may not be considered a con…)

Disqus or Google+

Use a different comment system, like Disqus or Google+. These systems require the commenter to be logged in before they can leave a comment, so it reduces the chance of a spammer being able to leave a comment.

Pros: Makes it really easy for some people to comment – if they’re already logged in, they can literally just type their comment and send it without adding any more of their details.

Cons: Not everyone has a Google+ or Disqus account. Although these accounts are easy to create, it might discourage someone from commenting if they know they’re going to have to sign up for something new before they can comment.

So there you have it – there are at least five alternatives to CAPTCHA that won’t annoy your commenters, and won’t decrease the number of comments you receive like CAPTCHA does.

The key point to all this?

If you have CAPTCHA on your blog, please get rid of it!

(sorry if that turned into a bit of a rant. I can’t be the only one who hates CAPTCHA, no?!)

More blogging tips:

How to reduce your bounce rate
How to find out how many times a blog post has been pinned
How to add titles and alt text to images
How to start a blog in 5 minutes
How to make a blogging media kit
How to set up a Facebook page for your blog
When to use ‘nofollow’ links