Hawthorn is based on the concept of affinity groups, a group of individuals who come together around a shared experience, interest or common goal. With Hawthorn affinity groups, you are free to start or join conversations and share useful resources with people in your community.
Good thing to consider, as we want users to feel comfortable what they are sharing is going to the appropriate group / private website they intend. Thank you for the informative link!
Sanitize input and/or encode rendered content to prevent attacks. We can start with looking at HTML injection attacks: https://www.hackingarticles.in/beginner-guide-html-injection/