OMG! I can’t believe you didn’t… You are hereby sentenced to 40 lashes with a wet noodle! 
There is a long standing request for server messages. You can lend your vote if you wish.
You might also take a look at Tautulli. Among its many useful features is the capability to send a newsletter on a scheduled basis. I use it to send a weekly newsletter announcing new additions to the server. It can be sent on an ad-hoc basis as well.
