If you have wondered why the Web seems filled with those annoying tests where you are required to read distorted text, and then enter it in an input field before progressing, read on. The quick answer to this question is we have to have them because Web site owners need to verify that the data entered on their site is actually entered by a human. So what else would be taking the time to type data into Website contact forms and comment boxes? The answer is not aliens, it is robot scripts.
Robot scripts, called ‘bots’ by Web professionals, are scripts, or programs, that are designed to trawl the Web looking for opportunities to enter data that their owners have an interest in seeing splattered as widely as possible. The content is spam that typically consists of unwanted ads. So if you are a Website owner with input fields on your site that aren’t protected by captcha tests, then your site will eventually become a host for ads that are not only unwanted, but contain content that is completely unrelated to your Website.
I knew about these bots and so already understood the need for captcha tests, but it wasn’t until I created flemingwebmedia.com that I discovered how prevalent and efficient these nasty scripts actually are. I received comments on my blog in the form of a link you can click, that advertised medicines you buy via the Web. Clicking these links might have taken you to an actual site, or maybe to a malicious site loaded with viruses. So for the integrity of the Website, and for the safety of visitors, captcha tests are a necessary minimum protective measure.
Captcha’s generate an image that contains distorted text. People can read the text contained in these images, but bots cannot scan the Webpage to find the text because of the fact it is contained in an image. Even sophisticated software that uses optical recognition hardware to read text will struggle to read the distorted text image.
Some sites use software called reCaptcha.
This captcha test displays two words, the second word is one that was not successfully identified by special scanners employed to digitise books. Using the concept of crowd sourcing for free labour, reCaptcha tests use humans to verify the word that scanners had trouble reading. Based on various responses, a high level of agreement on what the word is results in a positive identification.
So captcha tests are always employed as a security measure on Websites, and sometimes serve the additional purpose of utilising free labour for book digitisation projects.