Although virtual exhibits consisting of pictures and text are still common, educational Web developers increasingly employ techniques borrowed from interactive exhibit developers, video game producers, and museum educators to create compelling activities that fully exploit the strengths of the Web medium. However, such transfers from other learning environments to the Web pose unique challenges. For example, the effective teacher in a face-to-face learning environment responds to various cues about the learner's knowledge, interest, and ability. We do not have that ability on-line. Instead we must attempt to formalize within the programming of the activity much of the tacit feedback to which the teacher can react. This task becomes even more difficult when we take into consideration the diverse ways that people perceive and process information. This paper reports on current research into the impact of learning style on preference for on-line informal learning experiences. Building on our pilot study of user preferences for Web-based activity types (Schaller et al., 2002), we are currently developing ways to measure children's learning styles and testing hypotheses about learning style, activity preferences, engagement, and satisfaction. An understanding of individual differences in learning styles will provide valuable insights into the specific requirements of computer-based learning media and guide developers to design more engaging and effective experiences for a wide variety of learners.