Last.fm intern Joachim Van Herwegen has a quick look at listening habits by age and gender:
The sizes of the artists' names indicate how popular they are, while their position shows the gender mix and average age of their listeners. Based on the positions of the larger names, it’s already obvious which age category is most common amongst Last.fm users.
With age on the horizontal and gender breakdown on the vertical, artists on the bottom left are those popular among young girls. Top right are artists popular among older men. Red Hot Chili Peppers and Radiohead appear to hit the universal sweet spot.
I wonder how the graphs would vary across services. For example, I've been using Rdio for the past month, and nerd hipster music seems to be the hot theme around those parts. Hit up YouTube though, and everything is Bieberriffic. [Last.fm via Waxy]