No global private messaging?

I feel like I must be taking crazy pills. This seems so obvious that you should be able to privately message a user if they’re not in the same room as you, yet here we are. You went to such an extent to use the phrase “facebook like”, even naming your variables after facebook, yet as far as I can tell this fairly obvious and easy to implement feature of being able to message each other across the site is missing.

Have I missed something? I find this hard to believe. Thanks