I am a moderator on a Discourse forum.
It would be a great feature to see the local time of a user (at the right side of their username on each post, maybe?)
Visibility: not only for admins/moderators, but for any user.
For instance, I am located in Romania, so my timezone is gmt+2, meaning is 3 a.m. where I live.
I find it useful, when I reply to users…Other big freelancing websites, like for instance upwork, already use it.