Before arguing that "CAPTCHA's are a necessary evil", it pays to know the life time value of a user/customer for your site. It's likely that the cost of dealin

Before arguing that "CAPTCHA's are a necessary evil", it pays to know the life time value of a user/customer for your site. It's likely that the cost of dealing with the spam would be lower than the amount of revenue lost from your CAPTCHA-impaired conversion rate.