Users asked for the ability to see who subscribes to a forum, as this influences what they're comfortable posting to the forum.

We can't fully satisfy this request with forums as they currently work - we can show a list of contacts who've shared the forum with the user, and/or a list of identities that have posted to the forum, but not a full list of subscribers.

However, we may be able to create some other kind of group that meets this need - for example, a private group consisting of a host and a subset of the host's contacts (who may also need to be each other's contacts).