The author discusses a unique approach to blocking comment spam by utilizing a honeypot form field that is hidden using CSS. This form field is designed to trick spam bots into filling it out, while human users should leave it blank. By checking if the honeypot field is empty upon submission, spam comments can be detected and ignored. The author also provides a Validator control in ASP.NET that encapsulates this honeypot behavior for easy implementation. This clever method takes advantage of spam bots’ tendency to fill out form fields while ignoring CSS, offering a new way to combat comment spam.
https://haacked.com/archive/2007/09/11/honeypot-captcha.aspx/