Will CAPTCHA help ?

You or your organization have a site or a forum in the internet, you’ve spent a lot of time and resources on its creation, filling, development and attraction of visitors. Your resource is popular, the presented information is discussed by the visitors, they express their opinion and give comments. But…

Each owner of a site or a forum faces such problem as spam. And it is really a great problem, a site without protection in a couple of days turns into a rubbish heap of ads and references. The site will not interest a single visitor from now on. If your site provides a possibility to communicate, you’ll have to moderate it both from spam and those visitors, who wish to spoil your site.

Let’s single out two threats for the site, they are: spam and dishonest visitors and let’s examine them in detail.

How to protect site from bots?

In order to lower the costs on moderation, various methods were developed for spam protection. The principle is always the same: to automatically discern people and bots.

The most popular method is CAPTCHA – this is an annoying picture with curved and sloping symbols, which are offered to the visitor to fill in. It is supposed that spam bots won’t discern these symbols, but a visitor will. Captcha provokes great irritation, but if one wants to speak out, he has to fill in these symbols time after time, making mistakes and starting once again. At the sight of captcha and after input errors, many visitors leave the resource. Thus, captcha helps to protect the resource both from bots and visitors.

Other applied ways of protection consist in using fields, concealed from the visitors. Supposedly, a bot will fill in all the fields and a visitor – only the ones, he sees, and if all the fields are filled, the comment is considered to be spam and is not published. Checkbox is also applied, the visitor is asked to tick the box if he is not a bot. It is quite easy to write a script, which will tick the box and find concealed fields.

These ways will protect you from spam not more than 2 months, otherwise your resource has poor attendance and it is not interesting for spammers.

How does CAPTCHA protect from spam-bots?

With the help of algorithms and technologies of text recognition, the use of captcha gets less and less effective. The most part of captchas are passed  by connection to FineReader or OmniPage libraries, use of Cocke–Younger–Kasami (CYK) algorithm.

Writing of self-organising algorithm, recognising the symbols in captcha, doesn’t take a lot of time, but the efficiency of recognition is more than 50%. It’s not difficult for spammers to find ready-made algorithms for the most popular captchas in the internet.

If there are few variants of captcha, let us suppose, you use nonstandard captcha, then it is passed by plain guessing, when a robot sends random answers and some of them may suit.

One more way to pass captcha is to use human resource, the robot redirects captcha to a highly popular resource, sites of pornographic subject, file hostings and so on, a user of such site is offered to input an answer to a captcha and a robot inputs it in the needed site.

The use of artificial neuronic networks for robot training hightens their efficiency of discerning captcha. As a rule, recognition systems discern symbols better than people, what makes the impression that captchas are created not for eliminating the robots, but for eliminating people.

CAPTCHA is not a panacea from spam, the cost of manual recognition is 1-2 $ for 1000 recognitions. The use of such method of spam protection will facilitate your work on resource moderation and annoy visitors.

Do you still have doubts concerning the need for CAPTCHA in your resource?

How much time a day do you or your employees spend on moderation? Estimate the cost of this time, and if such task didn’t exist and these resources could be spent on something else, for example, on development? Summing up real losses and missed profit, you’ll get real costs.

Is there an alternative? The one, that would protect the site from spam, be invisible for the visitors and take less time for moderation?

Yes, there is – CleanTalk service.

CleanTalk is a service of automatic site moderation, which uses invisible for the visitor means. It uses multistep checking for eliminating spam-bots. The plug-in working principle is based on determining the message relevance and estimates the conformance of the written message to the topic of the site, blog or an article to which this comment was written.

The main advantages of the service is automatic protection from spam bots’ registrations, protection from automatic and manual spam distribution, message automoderation, adjustable lists of stop-words. It doesn’t load the database, as the messages don’t get into the base. Quick reaction to appearing of new spam bots.

There is economy on costs concerning moderation, and the released resources may be used more efficiently, than looking through messages and deleting spam.

Standard for installation in the site modules are developed for popular CMSJoomla, phpBB, WordPress, DataLifeEngine, IPBoard, vBulletin. API may be used for other CMS.

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