mrakk50 as the operators of discuss.flarum.org, we are experimenting with private messaging (Byobu) and might enable it for everyone at a later time. Right now we use it so moderators can privately message users.
As the Flarum core developer team, there is no plan to create a bundled/official private messaging extension at this time. We leave these kind of features to community extension developers while we focus on getting Flarum core to stable. The community has already created multiple private messages extensions which you can find in the Extensions tag here.
