Excuse me if this is a bit nihilistic of me, but I was noticing this morning when I was creating a new folder for some pictures that I'm using the full-on date: 20030919. I do this when organizing photos and many times downloads because otherwise I just can't find anything later - even sorted by created dates and all that (extract stuff from a zip and many times its date will be the day the file was zipped and not today). The only real way to find stuff on a 20GB Hard Drive is with general categories and then by date-time.
Anyways, I did that in my old permalinks as well (which are now IDs, but the old URLs remain). This was good back in the 90s because, well, the millenium was coming. But guess what? The next century is now 97 years away now. Creating a new folder with just 030919 is probably fine. URLs can probably be cut down a couple characters now as well.
The fact is, I won't be here for the next turn of the century, unless somehow I live to be 128 years old and most personal computer files weren't created until the 80s, so there won't be much confusing about those dates for another 77 years as well. And again, unless I'm extremely lucky, I'm not going to be here then either.
I guess I could think of the stuff I create as being eternal... There's more information being produced in the world every hour than you could consume in a lifetime. In a hundred years, finding these words won't just be like finding a needle in a haystack, but finding a grain of sand in the Sahara.
Wow, four paragraphs to justify cutting out 2 characters out of my dates... hmm. I must be in one of those moods. ;-)