It would be great to either have an automated tag group where unsubscribed contacts get tagged similar to the website leads tag group, or to turn on an "unsubscribed" email notification.

Some BrokerDealers require a maintained list of unsubscribed contacts, and right now to keep that maintained I have to run a notes report, filter for the term "unsubscribed", weed out the random notes that may have that term as well, then send it to a search, then tag the contacts with a bulk action.