The rooms we had issues with were public rooms that were discoverable via Matrix, with a couple of links on the web to direct people to them. The links to the rooms still exist in the same places, but ever since converting them to XMPP links rather than Matrix ones the traffickers have disappeared. I couldn’t tell you if that’s because XMPP is less popular with that crowd or if the tools they’re using to discover and spam them don’t work on XMPP. Either way it was a welcome change.

In my experience XMPP is easy to set up, lighter on resources, and the clients tend to work well across multiple platforms. We have small private and public groups using it daily with zero complaints.

Matrix tends to be more involved in setting up, and our group ran into issues where some clients weren’t working as smoothly or reliably as we needed for a primary communication platform. We also had a huge problem with traffickers of all sorts joining our rooms to spam their telegram links or CSAM. That hasn’t been a problem after more than a year on XMPP.