With the development of the Internet, electronic commerce, electronic markets, and digital economy, new business paradigm and new ways of business have been emerging and developing. The development of right and robust business models for electronic markets is a key for e-business success. This paper reviews previous studies and successful cases for e-business models. This paper presents strategic factors such as the business value and the source of revenue, products and services, business processes and technologies, and the characteristics of markets and relationship with customers and partners as a framework for developing sustainable and robust business models.