wesley123 wrote:wouldnt work, based on usernames etc. these are just scripts, and lately scripts can go around Captcha quite easily, causing Captcha to become harder and harder and more different, as a matter of fact I for example have an huge problems reading the Captcha 9 out of 10 times and it seems it has a fault tollerance since a lot of times I am quite sure I was wrong, yet the captcha was correct.
That is true in some cases, notably the most popular systems (such as reCaptcha) : this is because they primarily rely on images that can be analysed.
The system that we integrated into ocPortal was quite novel and innovative, in that it generated the captcha images using custom css injection, creating the captcha images on the fly within the browser without relying on easily analysed image formats. This made the captcha both easier to read and more secure against bots.
Admittedly, this would soon be circumvented if large numbers of people started relying on similar systems, but it certainly proved to be reliable during the 2 years that I was working for the company. Even if it wouldn't be a 100% secure fix, implementing captcha would still be an extra layer of security that could slow down the forum-flooding spammers.