Average song length, 1944 to 2008
 

Been noticing this with some of the recent albums I've bought: There's a lot more long songs - or at least fewer short ones (like, 2 min) - nowadays than there were in the 60's and even 70's. Though it seems to have peaked in the early 90's:
https://plot.ly/~RhettAllain/131/average-song-length/

It would all depend on the artist and the genre itself.

Well Slayer's Reign in Blood has some short songs for the genre, and old school punk rock had some ridiculously short songs, so yeah I guess I would just say it depends on the genre.

If you had a gun to my head, I would choose a shorter song over a longer one, just because unless there's a lot of variety in a longer song, it tends to get dull.

Maybe it's the result of a new generation with A.D.D??

There is a scene in the Gouge documentary where Gil norton says he mentioned to francis the pixies songs were too short so francis went to a record store and showed him that artist he grew up with like Buddy holly also made short songs, so i guess it does depend on the genre and the format an artist usually uses..