Just a few days ago, the Subway Sparklines post did gather some interesting reader comments on how, or how not, to visualize the historical ridership of the New York Subway.

Well, here is an alternative: Sha Hwang, visual designer at Stamen Design, developed "NYC MTA Ridership (since 1905)" [diametunim.com]. The concept is simple: absolute or relative ridership levels are indicated by subway line thickness, and users can navigate through time by using the slider in the bottom right. More information can be found on his blog.