I remember seeing someone else on HN use a five digit date years ago, giving the reasoning that it gives us a bigger perspective on our timeline and society.

I like the idea, but it muddies the message since we use standards for a reason. For example, if someone writes "In 13 I tried..." it's a bit confusing, but if they write "In '13 I tried..." it makes immediate sense since we have expectations about communicating dates.