I cannot believe I did not know this.
Ever since Google+ Communities became available, people complained about their Community posts automatically popping up on their profiles. This has been the default for public Communities. In fact, many Community owners on finding this out killed their public Communities and started over doing private ones.
I just today found out, hinted to by Bruno Škvorc, that there is a setting allowing you to change the default behavior. Unfortunately, it’s hidden away at the very bottom of https://www.google.com/settings/plus:
I’d love to see this become
- a per Community setting
- more exposed in the Community UI
But it’s good for a start.