In this paper we discuss three issues that are relevant to understanding the current state of marketing and consumer behavior in online sales channels and electronic marketplaces enabled by the Internet and World Wide Web (Web). First, how is the Internet used for marketing? It can be used as a new tool for market research, new product creation, product advertising and distribution, and developing consumer relationships. The second issue is how much money is currently spent by companies for Web advertising and by consumers for purchasing products and services online? Statistics illustrate explosive growth in each of these areas in the past few years. And the third issue is what factors affect consumer purchase behavior in electronic sales channels and markets? Three studies that represent current research in this area are discussed. Each study uses a different approach to study online consumer behavior in industries such as books, travel, and financial services. Online consumer behavior is an important issue for companies because they need to identify the characteristics of their potential online customers and use this information to effectively design their Web-based customer interface to succeed in this highly competitive new market.