EMAIL Marketing
Email marketing is a cross between print and web design. You have the evolving technology and digital distribution giving you a huge array of capabilities like web design, but it's a consumable and has a shelf-life and all of the challenges associated with print design. Even more so, it's such a direct form of communication that you have to be sensitive to privacy concerns of the recipient. CAN/SPAM laws are no joke.
I have managed many campaigns with list sizes anywhere from less than 100 to more than 1,000,000 and regardless of list size, it's always a carefully planned out and executed affair. Not only are you staying in contact and keeping the brand awareness fresh or conveying specific information, you're conducting market research. Questions like; how well engaged are the subscribers, What do my subscribers like and don't like, can all be answered inside the analytics.