The first (and possibly last) web toy is the Radio Tracker.
It takes data from various UK radio stations (as well as my own Last.fm feed) and displays track frequencies in terms of tracks per hour, tracks per day, and how many times each track has been played in any given time period.
In time I’m also planning on adding a graph that shows track popularity over time, a tool to show what played at any given moment in time (like reverse TV listings), and the ability to chose an arbitrary time period…
If you know of any other radio stations that publish their track listings in RSS format or via Last.fm, send them over to me and I’ll look at adding them to the tracker. I’ll probably reset the data on 1st June since the first is also a Monday…