This has come up a few times and perhaps I am missing it:

If you have a conversation with several members there doesn't seem to be any way to see a list of everyone in the conversation. Instead you only see something like "Joe Mark Sally and 5 others" But people want to know who those "others" are. Among many problems with this, it can lead to embarrassing situations if someone says something about someone else, not realizing they are a part of the conversation.