Now that's dedication, I'm impressed. I've watched the commentaries on maybe 2% of my dvd collection - I just don't get the time. I was an early convert to dvd and in the beginning film choices were very limited so I tended to watch every scrap of bonus material including a few comms, but as dvd's became more prevalent and my collection grew I found myself watching less and less of the extras (LOTR aside).
They're not something I really consider watching now (there's too many good films I haven't seen) but I might dip my toe if one came highly recommended.
Back to your question, no it wasn't the first. The original King Kong on laserdisc started it all off apparently, way back in 1984!