This is controlled by a permission – look at the permission sets and check the ‘viewing’ section where you can turn it on and off.
But remember – it will ALWAYS be visible to the forum admins even when turned off in all permission sets.

worth adding, that by default, only admins can see the email address…  you would have to change the permissions as Andy says to actually start letting others see the email addresses…   and as Andy says, there is a separate permission for viewing the profiles… so two permissions…

That works, thanks

cool.  thanks for the update.