Musicmetric is an interesting new social network site that allows you to see how a variety of musical artists and their work is being cited in social media.
The site is worth trying out, as is their API – take a look here: http://developer.musicmetric.com/
If musicmetric is macro-scale analysis then perhaps micro-scale analysis would look at connectedness of themes within pieces of music. Antton Nuotio does this in a beautiful piece of work here: http://anttonnuotio.com/dead_kennedys.html (recently highlighted on visualcomplexity.com