There is a great deal you can tell about a resource by simply looking at the page. What does the visible page tell us? What does the HTML code tell us?
Web Media Literacy means knowing enough about what websites and web pages are, and about the "ecosystem" that we call the World Wide Web, so that you can make quick sense of pages, and not jump immediately to the text.
Read about the First Visual Scan -- how many of these "markers" do you already notice, even if you don't think about them?