How to Use Rate Limiting Systems to Improve Your Chat Experience

Each individual person can't leave a comment more than every X seconds, which is better. That kind of per user system only works for a very narrow case and it actually works better when fewer people are there. Here would be my perfect rate limiting system that I feel like would solve a bunch of problems. Let's say every 30 seconds there can be a comment and the system would just pick randomly from everybody's last comment in the last 30 seconds that they typed into the box.That to me seems like a way where you're not cheating the system, but it can still scale and you as the operator of the chat have a possibility of following everyone.