I used to think the reasons for sharing this personal material were to get to know each other to provide a mental transition from the concerns mentioned to whatever else the group was going to do. And in thinking about this, I have just realized that talking to a support group has always helped me reflect in a more skillful manner. Not even to figure out what's happening, though that could happen. Rather it's to deepen one's experience, to be fully present to it. In a posting to the list, it would be ridiculous to start with a check-in and then move on to another subject.
Email works better when messages are focused on one topic.
But that doesn't mean we have to write great thoughts to share our practice. It just means we need to respect our experience, to be mindful of it. Even the little stuff. Our everyday stuff is, after all, the main part of our practice. It may give us subjects to consider at length, but even if it doesn't, it keeps us in touch with each other in a mindful way.