I had to typin over 10 times the Captcha at the registration form. And i was sure i typed it over correctly.. Just before i was about to give it up it suddenly said it was correct, and i was registered..
Spoken about usabilty, You should for fun log how many REAL PEOPLE try to register, and leave because the captcha was typed over wrong..
Nothing wrong with a catcha, but this one is totally incorrect.. It says that you typed it wrong 10 times while it typed it 100% sure correctly.