WP-reCAPTCHA is a WordPress plugin for fighting comment spam. It has two main features, anti-spam reCAPTCHA and MailHide email protection. Since, I already have Akismet and WP-SpamFree in my blog, I am not going to use CAPTCHA feature from this plugin. MailHide feature is what I want. I enable it by getting Mailhide API key from their website.