A List Apart has long been a fantastic source of knowledge and inspiration in terms of both website design and writing, but on top of these accolades every now an then it manage to completely floor me. Sometimes it's because an explanation finally hits home after years of misunderstanding, but other times it's simply by providing a piece of information which is simultaneously brand new and yet perfectly obvious. The type of fact which leaves you a little wide-eyed, questioning your very purpose of existence. A mind-blower, if you will.

That's what happened today whilst reading the (brilliant) article/excerpt on Web Typography: Numerals. The article is well worth a read just for the thoughts on how the web finally makes footnotes genuinely useful (and, in doing so, guilt trips me about how these same ideas have been sat unacted upon in my head for years). However, it was a simple comment near the start that struck me like lightning:

We have at our disposal ‘uppercase’ numbers 0123456789 called lining or titling numerals, and ‘lowercase’ numerals 0123456789 called old-style or text numerals.

Wait... what?! Numbers can have cases? I read the sentence once, thought "that's strange", then read it again and noticed the different cases. These different glyphs are subtle but still instantly recognisable, yet I have never realised they existed before. Such a simple little thing which makes complete sense. Much like the recent viral expose of Papyrus or the infamous Fight Club burn marks, I get the feeling that text numerals are now going to be one of those things I just can't not notice. Which is equal parts infuriating and awesome.