I should have enabled and loaded this module a while ago but as of February 1st it’s now active. It allows you to block specific users so you don’t continue to receive messages from them. On most clients (like Pidgin) you can just right click the user in question and click “Block”. With the wave of XMPP spam going around I felt it was absolutely necessary to have. Read more on it here.
I’d also like to mention that I’m continuously looking into ways to make XMPP.is more user friendly through Prosody modules. I haven’t had a lot of time recently but I’m working on it! If you have any suggestions feel free to contact me.