How do YOU classify music?
 

What do you consider to be a genre and what make something rock? According to Rolling Stone magazine Bruno Mars is rock now, REALLY???
What are you thoughts what makes a genre a genre??

Muscle Punk Horror Metal

Blackened White Metal

Is this thread more about the boundaries & distinctions of genres or more about Bruno Mars?

Well if you are talking about Bruno, Wikipedia has his genre's listed as "Pop, Reggae, Soul, R&B, Funk, Jazz, Blues, Rock." He is a Pop artist who performs songs in those styles more so than a full fledged Jazz artist etc.

I divide popular music into just two broad categories. Rock and pop.

Rock music is loud and at least somewhat aggressive, with a major focus on the rhythm.

Pop music, in my scheme, is not very loud "mild-mannered" music with a major focus on the melody.