You can hide any/all of your community memberships. This will hide them from your Member Of list, your Posting Access list, and your Friends list (on your userinfo page only). You do show up on the community's userinfo page, however. We do not want any person to be able to modify somebody else's userinfo page.
What do people think? Is this a good policy, or should it be different? Should we allow hiding memberships only enmasse? Or is it good to be able to hide specific ones?
Thank you for your feedback. This discussion will be open for a few days while we gather information on what people think.