What the **** are breakdowns in metal music?

it used to just mean bits where the song slows down in like a bridge type part so the song could ramp up again, but now it means bits that go "da da da da da da da da da da" (playing the same chord over and over)

I don't know how old you have to be to be an old school fan but I've been into metal since 95' and yeah breakdowns are total BS 99% of the time, but every now and then a band does something interesting with them, like After the Burial, here's an example: http://www.youtube.com/watch?v=jH9tLxAHRaE (first breakdown at like 1:30)

Considered/supposed to be the most brutal part of a song. Beat changes, no vocals, just heavy music.

for the calor.