Want to see how Wigan, Swansea, and Fulham rose to the Premier League? (Before they fell back out again.) How about teams from the West Midlands in the 70s and 80s? Or just the long (and generally sad) history of teams called County?
Terrific! This page is a simple experiment with D3.js and historical English football league data taken from the wonderful RSSSF. It shows the overall league position of a team over time. For example, with a 20-team top flight, first place in the second tier is 21st overall. Use the controls on the right to choose teams (no more than 10!) and the data range to view. (If you know how, then fork on GitHub at smcgivern/historical-league-positions.)
The data behind this chart is also available as a CSV file.