Some information visualizers, especially those working at newspapers and magazines like this one, worry that complex visualizations make beautiful data art, but that they risk confusing readers instead of enlightening them. I asked several people in the field what they think of the styles that epitomize "data vis" today – and how to use them well.

One of the most common characteristics of recent data visualizations is a huge number of thin, overlapping, and semitransparent lines. From GPS traces to national development statistics, computerized information visualization enables us to plot hundreds, even thousands of points instantly and to use partial transparency to let readers "see through" points to others behind. Probably not what William Playfair had in mind when he