Reply management is an important, but often overlooked part of meaningful use of email as a connection point between brands and customers. We rely on our tools to auto-filter unsubscribes, errors, etc. But there are some replies they can't interpret that require you to opt-out or remove an individual. Real people-written replies often expect real people-written responses. OR, if they don't, they're often delighted just by receiving a reply. Reading through email replies can provide helpful qualitative feedback from a customer perspective.