Use BSK Gravity Forms Blacklist as a Gravity Forms Spam Filter.
Maybe you have already enabled reCAPTCHA on your form, but some real humans submitted spam messages because they filled in the reCAPTCHA. These messages are about chance to earn XXX million dollars, selling cheap SEO, outsourcing services and someone want to tell you an interesting news.
Because these spam messages have common keywords, such as "outsource", "outsourcing", "SEO", "interesting thing", "interesting news" or "a chance to earn". Then you may BSK Gravity Forms Blacklist to block those messages.
How to setup it as a Gravity Forms Spam Filter?
After you apply list to form field then when validation message will be shown out if users input match your item.
With this example you may do a Gravity Forms registration form to block some area.
When submit form:
Gravity Forms will show validation message for the field.