The Internet is becoming an important tool for the realization of day-to-day activities, which leads to a new level of interaction between users and software systems. This new scenario presents endless opportunities as well as enormous challenges. In order to tackle these, user-adaptive software systems have been recently used. These technologies aim to allow computer systems to dynamically modify their content, structure and presentation for better delivery of the available resources, while considering the user's interest and behavior, and most recently, mobile environments. This chapter overviews the newest technologies in the area of user-adaptive software systems applied to Web environments and proposes a set of directions for the future development of Web Usage Based Adaptive Systems in the new Internet environments.