A marketing agent works to match a company with a media outlet like a radio or TV station, social media page, or website to advertise a product or service. As a marketing agent, your duties are to find the best media matches for your clients, aid in the creation of sales materials, and make advertising deals on behalf of clients. Other responsibilities may include creating and managing client records. Because you often conduct a significant amount of marketing work through the Internet, you must maintain a reliable, professional online presence so clients and advertisers can communicate with you.