The purpose of this research is to draw implications and insights for the design of microlearning. This study investigated two questions concerning (a) what kinds of topics and knowledge are relevant to learn through bite-sized content and (b) how to design bite-sized content effective for supporting adult learners' microlearning opportunities. We conducted a research study with adult learners who are mostly graduate-level students and R&D professionals working in the fields of science and technology in Korea. To examine their experiences and perspectives about microlearning, we gathered data through the survey and focus group interviews. Overall, this study found that adult learners tend to have some separations about the topical areas perceived to be relevant for e-learning and microlearning. The design of bite-sized content that takes the modality of video and can be consumed within 3-5 minutes was considered to be the most relevant for microlearning. In conclusion, we discuss the implications concerning the potential and challenges in designing microlearning.