There is no specific way to get admin notification of these events. They can be notified for many of these things if they are subscribed to a particular asset or a forum but there is no general way to say for all assets/forums in a community to notify them.

The best that can be done is for an admin to go to the Communities page, go to the community, go to the Audit page and do an audit query for forum create, topic create, forum post, reviewer rating, or user rating. Feed back is part of rating, can't get a feedback without a rating.