For mailing lists, there are some solutions:
I am not aware of others.
Ideally I would like a tool for organization mails, and with access control. Cc'ing and/or forwarding to this email address will make the emails part of the feed. It also helps in managing the context for activity, since the feed name (which should be necessarily dynamic and easy to create) represents the context. Since the information is typically sensitive, the feed should only be available to the group. Perhaps only to members listed in each email item.
It is much better approach than mailing lists, because RSS aggregators help you manage multiple contexts in much nicer way. But "subscribing to feed" should be made simpler - with help of good integration, or perhaps a special feed that allows publishing of new feeds and allows easy subscriptions.