Comments are a very good way to engage users in your blog. However, there comes a time where your blog becomes popular and it is flooded with unnecessary messages. Some in a form of ads, others are saying useless comments that doesn’t add any value to your post, and others seem to be automated. These are called spam and the moment you see one, you have to deal with it as soon as you can.
The only way to deal with spam is blocking them using CAPTCHA. CAPTCHA is an acronym for Completely Automated Public Turing Test to tell Computers and Humans Apart. It is a technique used to control comments from automated bots.
Here’s how you can block comments in WordPress using CAPTCHA: http://www.wpbeginner.com/plugins/how-to-block-spam-comments-in-wordpress-with-captcha/