Question:

Is there a way to show users which agents are following a ticket?

Answer:

You can retrieve the followers for a ticket within the email templates using ticket.getAgentParticipants(). This  example code loops through the list of following agents and displays their names and email addresses:

{% for agent in ticket.getAgentParticipants() %}
{{ agent.display_name }} ({{ agent.primary_email.email }})<br/>
{% endfor %}

You could add the same code to the portal ticket management pages to display a list of following agents - add it to the view.html template under Tickets.