Yes, users can subscribe to any news articles you publish by inserting their email addresses by clicking on 'Subscribe' option available next to login box, as shown:
For unsubscribing from News section, users can click on the unsubscribe link that they receive in the email when they confirm their subscription. as shown.
In case the end users have lost that email, then they need to contact Kayako to unsubscribe from News.
Sukhpreet Anand