Since no one else has mentioned it yet, this is a milestone. DVD is now older than laserdisc was when DVD debuted, and about as old as VHS was.
I did a bit of reminiscing around the format's 15th anniversary, but to sum it up 20 years ago today you could find DVD players in stores and many of them were playing the Panasonic demo disc, but actual movies would not be available until mid-March and then only in a few test markets. I thought the demo discs looked terrible in the stores, but having secured copies of most of them I've found they look pretty good at home. At the time many of us videophiles saw DVD as a threat, as we feared it would be full of compression artifacts that were worse than any analog noise found on laserdiscs, yet the industry was already set on killing off that format by then.
DVD was marketed more towards the general public than laserdisc, and thus consensus was that people wanted movies that would fill their 4x3 TVs without "dem black bars". While many DVDs included 4x3 and proper-ratio versions together, some did not. Some DVDs were widescreen-only, while others were only 4x3 even if a letterboxed transfer existed on laserdisc. Widescreen DVDs weren't always in 16x9 format either, resulting in a windowboxed picture on the few widescreen TVs out there at the time. Those who had those were used to adjusting the picture for every movie anyways.
Here's some clips from those early demo discs (I'm STILL looking for the one from RCA, if anyone has it!) along with intros and promo clips included on some of the first movie discs:
One detail they don't quite get right is that the first players were actually in stores several WEEKS before any movies were available, even in the test markets. Demo discs were the only discs that the stores had to play, and they looked TERRIBLE on the TVs there but watching them at home they've looked fine- just further showing how much difference a properly-adjusted TV makes. All major studios did get on board before DIVX failed, though Fox and Paramount were the last two- and Fox initially overpriced most of their titles at $34.99 each.
Some of MGM's DVDs were the very first dual-layer discs, holding both a widescreen and 4x3 version of the movie on one side. Oddly I've never bought an MGM disc that has that, all have been 2-sided so they must have given up on that rather quickly. Terminator 2 was the first dual-layer disc to fit a longer movie on one side, rather than overcompress or split it onto 2 sides.