Recently, my blog page received a lot of spam comments (approx. 100 spam comments a day) from different ip addresses. Thus, I cannot take the advantage of "Host Block" plugin to block those spammers.
Is there any plugin ask the comment writer to look an image code and type in the code before they send a comment to my blog? The code is an image that cannot be read by a machine. Thus, it prevents automated programs sending spam comments to my blog. Don't know how to call this function. The image code like this http://www.register.com/retail/whois.rc ... E0.euapp04 (Please type in any domain, such as google.com, and press ok. You will see the image code.
Or any other better way to stop spam comments?
Thanks a lot!