reCAPTCHA Lets Your Users Register Easily (on WordPress, Joomla…) While Digitizing Books and Blocking Spammers

I’m sure you stumbled upon on a CAPTCHA code somewhere on the Internet. It’s an image with a few distorted characters that you must recognize and enter in a frield in order to continue to a desired part of a website. CAPTCHA stands for Completely Automated Public Turing test to tell Computers and Humans Apart. CAPTCHA’s are often placed within registration or login forms.

The function of the CAPTCHA system is to prevent spam and automatic registration to various sites. But some people got together and found an even better use of the CAPTCHA system; helping to read poorly scanned books.

How Does CAPTCHA Work?

Why was CAPTCHA even created, you might ask? The web is a lot different now than it was several years ago. Spammers are practically everywhere, trying to register on countless forums and sites with their spambot systems. So people created registration processes that were able to differentiate actual humans from spambots.

The CAPTCHA software would generate a random set of letters and numbers in an image file, and you had to read it (to be more precise – recognize it) and enter into a box. If correctly entered, you would be recognized as a human instead of a spammer.

Different CAPTCHA codes (Image credit:

With time, the spammers developed methods for recognizing the CAPTCHA code, the characters became more complicated. Lines and colored backgrounds were added, characters were rotated etc. Currently, it works quite well.

What Is reCAPTCHA?

When CAPTCHA got used throughout the web, some asked: hey, OCR software is not 100% perfect, could we use the web users to help us out? Yes, they could.

OCR stands for Optical Character Recognition, and it’s a technology that can read text in scanned documents. Unfortunately, sometimes the scan is so low quality that it can’t be read with a machine. But a human can read it and this fact is the foundation of reCAPTCHA.

The method behind the reCAPTCHA system is to take these low quality scans and put them on registration forms all over the web. The image is not alone; it’s paired with a word that the system already knows. Once a user opens up a website, he will enter both words correctly. The system will now presume that a user really has entered the right answer for the low quality image.

Different reCAPTCHA designs (Image credit:

You’re practically forced into entering the correct words since you can’t tell which one is the actual CAPTCHA and which is the scan. Most people don’t even know they are helping read scanned words. If you somehow enter the known word correctly, and you fail to guess the unknown one, well, good for you. Spambots get rejected and reCAPTCHA did its core job.

Of course, the reCAPTCHA system won’t take your answer for granted; it will take answers from a lot of other people and when it gets convinced that the unknown word is spelled right, it will put it in the archive and give you some other poorly scanned word.

Why You Should Use reCAPTCHA on Your Website?

There are a few reasons why you should use reCAPTCHA as your spam protecting system:

  • By using reCAPTCHA you and your users are actually helping to digitize books;
  • You may have blind people among your users. The audio test that is a part of reCAPTCHA allows those users to easily login;
  • Over 100,000 sites use reCAPTCHA and not just the small ones, but the big ones like Facebook or Craigslist;
  • It’s pretty secure. There will be no spammers entering reCAPTCHA protected sites;
  • Easy to use – due to its popularity, there are many WordPress plugins, samples of PHP code and other easy-to-install plugins; You don’t have to worry about anything else; image generation, checking and validating is done on reCAPTCHA’s servers.

So, if you’re having troubles with spammers, try out reCAPTCHA.


Nikola Krajacic

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