May need more details. There is a theme component that adds a “Follow” button. Generally one needs to create an account to receive email notifications of the forum.
That being said you can create links as an RSS feed.
If it is your main site blog and you have a button there. You can likely post a link for tha main site blog.
There is also a Follow Plugin for following other members
The availability of using the plugin will depend if Self hosted or if your hosted plan includes it