Reduce the refresh rate drastically, augment the number of messages fetched at once (let's say 200), and display them slowly. Should reduce 20 times the load on DB while making no sensible difference for end users anyway.
Ok interesting idea. My one fret here would be that it would decrease interactivity on the site. Sometimes people send messages in response to each other, right? But nonetheless I'll experiment with increasing the refresh rate and maybe strike a nicer balance
second this, I managed a brief conversation with someone when trying this out and it was great, a few other messages seemed to chime in as well. perf/eff can be improved as mentioned above but would lose the fun, imo