It's more important than ever before to design content that is mobile-friendly instruction. The number of adult learners who have access to mobile devices grows daily. Although there is certainly still a digital divide between those who have a mobile device and those who don't, the mobile-device gap between the two camps appears to be shrinking.
Going mobile stats
The Association for Talent Development (ATD) recently shared this relevant infographic full of stats that emphasize the importance of understanding the changing environment in which learners interact with instruction.