Since 1999, the idea of a library portal service, called "MyLibrary," has been well discussed and conceptualized. The service is an integrated approach to build library online service components into one user interface, which can be personalized and customizable based on users' preferences and interests. North Carolina State, Cornell, and Virginia Commonwealth Universities pioneered their models, and similar models have been implemented in many university libraries since then. This chapter will provide a brief history of library portal development and discuss how the concepts and services of library information portals are defined and developed. It will use a medical information portal, MyWelch, to illustrate how a library portal service can be an ideal environment to understand users' information-seeking behavior and their needs, and for library and portal developers to continue their work in order to respond to such needs. The chapter will discuss some issues related to further developments and what portals will become in the future.