This article presents the description of the objectives, the structure and the functionality of an interactive system intended to focus the teaching on the performanceof the student and to resolve problemsdetected in Internet use for distance learning. The system adapts to the information and communicationneeds of the different types of users. This adaption is done through user modelacquisition fromthe data available on the students and user interaction with the system. WebDL,the systemwehave developed, is the result of an effective combinationof techniquesused in intelligent tutoring systems, adaptive hypermediaprograms and learning apprentice systemsfor software personalization. In the initial stages, WebDLis being used for the personalization of the presentation of the exercise part of the machine learning courses at UNED(The Spanish National University for Distance Education) ComputerScience School.