What is e-commerce, and how does it affect promotion?

"E-commerce refers to the development and maintenance of a company’s website and the facilitation of commerce on the website, such as the ability for customers to order products on line, to get questions answered about products, and for the company to introduce new products and ideas. E-commerce can include special components designed specifically for separate target market segments, such as information boxes or games. The ease of use and ability to comparison-shop is driving millions of people to the internet to purchase goods and services. Major retailers such as Walmart are quickly increasing their web presence in an effort to stay relevant in this ever-changing business environment and to attract even more loyal customers who have made the switch to doing most of their shopping on line."