I am also looking for option for making certain users and groups invisible. Option to be invisible can be granted by admin to certain groups. Reason is simple, some would like to join the forum and not be seen. And yet, people in general would like plugins like who’s online.
I often want to make some changes to my forum but i get so many messages once online. A few minutes changes ends up wasting my half an hour.
There is option to be anonymous but the admin section or certain group section is not available on it.