Use comment blacklisting (4/4)

If your website is built on WordPress, use Contact Form 7 for your contact forms, install Akismet to filter out basic spam (be sure to add it to your form fields), and then add words like guest post to your comment blacklist. The exact words you include in the blacklist depend on how bad your guest post spam problem is, your tolerance threshold for losing a legitimate contact, and the nature of your site. Typically we just blacklist the words guest post and handle stragglers on an individual basis.

Contributor: Joe Goldstein from contractorcalls.com