When the Web began to develop at
rocket speed at the end of the last century, so did spam. Spam quickly turned
into a nightmare for many sites and webmasters desperately sought a solution to
the spam problem. Such a solution was offered quickly and it was called CAPTCHA
(Completely Automated Public Turing test to tell Computers and Humans Apart).
The function of captchas was to stop spambots from doing their jobs.
As it turned out pretty soon, spambots (and their creators) aren't that stupid and they quickly figured out ways to outfox captchas. Nevertheless, captchas still manage to filter at least a portion of the spam a site is getting and this is why they are still in business.
However, this comes at a price. Captchas stop not only spambots but they are an obstacle to legit human visitors as well. What is worse, captchas stop only humans but search engine bots as well. If you have content that is accessible only after a captcha is entered correctly, it's quite obvious this content is out of reach for search engine spiders who even if they could, wouldn't bother with filling in captchas ?? they just move to the next site that is more welcoming.
As it turned out pretty soon, spambots (and their creators) aren't that stupid and they quickly figured out ways to outfox captchas. Nevertheless, captchas still manage to filter at least a portion of the spam a site is getting and this is why they are still in business.
However, this comes at a price. Captchas stop not only spambots but they are an obstacle to legit human visitors as well. What is worse, captchas stop only humans but search engine bots as well. If you have content that is accessible only after a captcha is entered correctly, it's quite obvious this content is out of reach for search engine spiders who even if they could, wouldn't bother with filling in captchas ?? they just move to the next site that is more welcoming.
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