Enable a way to see songs play count trends
For example - in 2010 songs A & B were played 10 out of 20 times each - but B was played in the last 10 concerts, while A was in the first 10 of the query period.
it could be implemented using some kind of discrete derivation.
You can, instead of just taking a counter of the number of plays - do a weighted sum - for example, playing a song in the last concert would worth 2 points, song that was played in the one before it worth 1, 0.5 and so on (such that the sum of the weights divided by the number of concerts would be 1), and call it a song Score/rating or something
You can also show a graph of play count cumulative sum for a specific song