I actually don’t get this question very often. The question I often hear is, “Can you help me get CAPTCHA set up on my site/blog/etc?”. Usually people just want it but a lot of times they don’t think about whether or not its a good idea.
Think about it this way. If you didn’t know cops exist, and you wanted to drive to work. You know it takes maybe 20 minutes at 60 miles per hour, so naturally it will only take 10 minutes if you go 120 miles per hour, right? Well, then you’ll discover the cops, and hopefully you won’t discover the high speed crash.
This is kind of how CAPTCHA can be for your blog, website, and more. Naturally the negatives aren’t as harsh as being arrested or a high speed crash, but they might be pretty serious for a business.
The main reason someone would consider using CAPTCHA on their blog to begin with is probably to try and prevent spammers. You open a website, and over time you’ll notice that as your site gets found online the spam starts flowing in. It’s a bitter sweet feeling. If the bots can find you, then people will start finding you, but you don’t really want the spam bots on your site.
Normally to alleviate the extra work of dealing with all the spam many will use a CAPTCHA image in their form to prevent these automated bots from posting. But if you have a website then I’m sure you’ve visited another website. Have you ever visited a site with CAPTCHA and had difficulty posting anything because you can’t read the letters?
If you can read the letters then most bots can actually be programmed these days to read them as well. So these letters are usually very hard to read. Do you want to risk a potential contact getting frustrated and leaving the site?
A while back I found a study that a developer had created. This particular developer tested CAPTCHA on 50 websites he was maintaining for his clients. I can’t find the link to it right now or I’d post it for you. The first 3 months he had 25 sites with CAPTCHA and 25 sites without, for the next 3 months he reversed it. So he had the results of a pretty decent study.
He found on average on his well visited sites, that about 7% of the form submissions were spam, if I remember correctly. Now on the months that CAPTCHA was in place he would see that all of spam failed to submit the form properly, but the interesting part was that an additional 4-5% of form submissions were also failing. These were new unique visits as well, a total of 11-12% of failed submissions, compared to only 7% spam on the months with no CAPTCHA.
Maybe in the beginning of your site when Spam is high and human visitors are low, comparatively, then you can afford to take this risk. But even considering the time you save if you have a start up website I would think that every single contact would be important. Can you really afford to loose 1 out of every 20 visitors because they can’t get past your CAPTCHA?
Now if your offering or their reason for posting is so very compelling that they feel a strong need to do so, then they might fight through it. But the less compelling the reason for posting, the easier the person will give up. I don’t know if I want to take the risk of loosing 5% or even more. I think I’ll just find other ways of dealing with the Spam.