Current interactive software systems try to offer many features and a user-friendly interface to aid the user. However, where one system may suit one user, another user may find it difficult to use, because each user is different. User modeling techniques have been applied to make a system suitable for different users. This paper surveys research works for developing interactive systems that use user modeling techniques. After presenting the systems and techniques, we introduce a system called the Intelligent Syntax-Directed Editor (ISE) as an example to show how this approach can benefit the user as an intelligent tool. The ISE assists the user in (1) using the editor more efficiently through ISE's active suggestions and on-line help and (2) program development through the syntax-directed editor. In applying user modeling techniques, ISE builds a profile/model of the user and, based on this model, ISE offers a suitable amount of help and advice depending on the proficiency of the user toward the system. The ISE is implemented on a VAX/780 computer to demonstrate its ability to volunteer advice