In Live Blog it's easy to enable DNN's CAPTCHA.
reCAPTCHA
Using Google's reCAPTCHA is just as easy. Set the CAPTCHA option to "reCAPTCHA", select a theme, and provide your public and private key.
You can generate your keys by signing up for free at http://www.google.com/recaptcha
Step 1
Navigate to Manage > Administration > Comments > Captcha > Select reCaptcha from dropdown
