Recent years have witnessed the rapid expansion of online technology and its use in education and training. The Internet and web technologies are used for courses of study as small as self-paced tutorials and as large as entire degree programs. Web technologies are currently used in many ways including distribution of traditional classroom materials, asynchronous and synchronous communication among students and instructors, multimedia presentation, and interactive simulation. Although the body of published research in web-based teaching and training is large, it is relatively young and incomplete. Existing theoretical and exploratory research needs further synthesis and empirical validation. Meanwhile, rapid technology changes have created opportunities for new theoretical and exploratory investigation. This paper points out some significant unanswered questions regarding web-based learning and training. We argue that only by answering those questions can the true power of the web to support learning and teaching be understood and, thus, fully exploited.