Problem: E-learning has become a standard in many organizations to train its workforce and build an information network that encourages collaborative knowledge sharing. As a result of technological and global factors, the complexity of delivering successful e-learning courses and products is an increasing challenge for subject matter experts and instructional designers. Online training courses have become blended learning environments, comprised of synchronous and asynchronous modes of delivery, multiple media forms, and global and localized audiences to meet the demands and flexibility it affords. Successful blended e-learning is more than simply mixing online and live instructional modes; it can also include a combination of multiple media types, technologies, and communication modes. E-learners have become multimodal learners, with the ability to adapt to multiple media forms, environment types, and tools. Key concepts: Understanding the complex interaction of technology use, collaborative knowledge sharing, and media can facilitate more effective communication exchanges between instructor, content, and learner. Some concepts that help describe the complexities of blended e-learning include technological appropriation, technological accommodation, media richness, media synchronicity and naturalness, blended e-learning, and collaborative knowledge sharing. Key lessons: Research trends suggest learners appropriate technology and media forms, and evaluate usefulness based on a range of factors, including richness, experience, perception, and recommendation. Blended learning environments add complexity by mixing spatial (distributed and colocated) and temporal (asynchronous and synchronous) components with increased levels of collaborative knowledge sharing. From these research trends, the following best practices for developing e-learning are recommended: (1) consider media richness factors and user preferences in media and tool selection; (2) encourage personaliza- ion to foster trust; (3) facilitate collaborative knowledge sharing both inside and outside the training setting; (4) balance roles as knowledge facilitator, coach, and information manager; and (5) invest additional time in both course and instructor preparation. Implications: Blended e-learning presents a number of challenges for subject matter experts and designers of instructional content. Subject matter experts must consult with instructional designers and consider the different media platforms, environments, and formats that optimize the best pairing of content with delivery mode and media type. Content experts and designers must collaborate on methods of effectively adapting course content to account for perceived richness, user experience, and task complexity. Instructors must also invest additional time in planning and accounting for user preferences and communication practices in online training.