I got a lot of interesting tweets about this (Thanks!) and wanted to see what you all have to say >140 chars.
Three anecdotes that led to my sending the tweet:
• I've been thinking quite a bit about Branch use cases, and I have a hunch that in many online group settings, needs for privacy and exclusivity get confounded.
• I was recently invited to a small Facebook group for community managers, where <100 people mostly trade tips and ask for advice. They want exclusivity, but they've ended up defaulting to privacy. Why is this?
• There's a well-known listserv for women in technology, which (to my knowledge) is billed as private but is ultimately still a listserv, so emails do occasionally get forwarded. Do they expect true privacy?