From the Health Literacy Online website section on Why this Guide?:
Many web users struggle with even the most basic tasks—for example, using a search function, navigating from a drop-down menu, and scanning a webpage for relevant information. This may not matter too much in the context of an online news article or confusing eCommerce site. But the stakes are raised considerably when a person is trying to sign up for health insurance, learn about a new medical diagnosis, or look up how to correctly install a child safety seat. And today, these activities are more likely to occur online than off.