It's because this forum's captcha like everything else is very outdated.. Forums needs an update.. a new skin :S
No the staff has been working on it since 2 years ago. I had a green name on my old account when I posted this exploit. I can't remember the username or password but the account is very old.
The captcha is broken with just google chrome alone! I cannot find my old post about it but a simba script can break the captcha in less than 5 seconds. Yes I know it's ridiculous.
Replication from my old post when I had a green name:
*deleted*
Imagine all the other stuff you can do <.<.. Anyway my 2 cents: Don't use stupid word captchas.. The captcha breakers out there can destroy those word ones unless they're really really really good!
Btw. The Registration php captcha only has 40 images. So.. scripts can learn them