To The Tune Of ... What?

CHORUS:
You can read them on the mountain,
  in the valley far below,
But the words without the music
  make up only half the show.
Since it costs so little effort
  and it's such a helpful boon,
Please be kind to other filkers:
  always name that tune!

Music goes by generations,
  music goes by fads and styles,
What hits YOU between the eyes
  may miss another fan by miles.
At the top or at the bottom,
  tell them where it can be found:
Since it isn't always obvious
  just write it down.

  (CHO)

As you listen to the music
  in your mundane life each day
On the road or train or sidewalk,
  at your work or rest or play,
Though you hang out with companions
   whose tastes are like your own,
There's no guarantee those songs
  are univers(a)lly known.

  (CHO)

From Child ballads up to hip-hop,
  from metalhead to blues,
There are genres by the hundred,
  more than anyone can use.
Though you're sure the tune is famous --
  it's the song you always hum --
Don't assume we'll recognize it,
  tell us where it's from!