The web has always celebrated expression in more than just text. Web pages can be rich in the variety of ways that they express ideas. They can interleave photos, drawings, diagrams, sounds, animations and videos with plain and familiar writing.
Many argue that this richness of expression is requiring and, therefore, cultivating a new sensitivity in web users to how ideas can - or should - be well expressed. Some like to refer to this as a new form of "literacy".
Traditionally we have thought of this word as meaning fluency in coping with ideas that are conveyed in writing. But in a medium like the internet we seem to require new forms of fluency, new sensitivities to the expression of meanings. In a sense these are "new literacies"
Because Web 2.0 encourages users to participate in this meaning-making, the pressure to develop such new literacies is all the greater. Web 2.0 users are more active in constructing images, diagrams, movies (and, yes, text) - as well as the more familiar experience of "reading" those images, diagrams, movies and texts made by others.
Here is yet another video explanation of Web 2.0 and illustrating many of the characteristics of Web 2.0 expression - and, by implication, the literacies it demands