You can use knowledge base articles feedback to improve communication with the customers. When used in combination with likes and dislikes, feedback can show you the weak points of your knowledge base that prevent it from performing better. Also, feedback is different from using comments: it does not appear on the article page, so there is (almost) no value in using it for spammers.
Articles feedback setup
To enable feedback in articles, go to MinervaKB –Settings – Feedback and toggle this switch:

You can control in which cases to display it: always, after like, after dislike, after like or dislike.

Choose the one that fits your knowledge base better. You can also change any text or color that is used in feedback form here. For example you can use different messages for feedback shown on like vs dislike.
Feedback submission
After you save the settings single articles pages should start to display feedback form.

Note, that submit button is disabled until the customer starts typing a message. This is to prevent empty feedback.
When customer submits the feedback, he sees a success message.

Feedback management
Submitted feedback appears in feedback list on article edit screen under the related articles box. You can view them here and delete not useful messages.

Also, MinervaKB analytics Dashboard has a section dedicated to knowledge base articles feedback. You can quickly check which articles received feedback recently and take appropriate action. You can also remove feedback entries from here.

Conclusion
This is basically all you need to do to start using feedback in your articles. You can also check this short video guide on using feedback in your knowledge base.