Slate says 12/12/12 isn't all that cool a date, really - not as cool as 6/23/1023

Slate has a tongue-in-cheek item today ranking various dates in history "according to universally agreed-upon standards of coolness such as roundness, symmetry, and coincidence with numbers of mathematical significance."

12/12/12 doesn't make the top ten of all time - it doesn't even make the top ten of dates that people living today might have seen or might see.

It's a clever piece, worth checking out here.

I have one question: why does the writer think 6/23/1023 is so cool? It's not a mathematical constant that I can think of - the best pi date (3/14/1592) and best e date (2/7/1828) are in the list - and there's no symmetry or pattern. What am I missing?

UPDATE: Avogadro's Number, of course - d'oh! I never was any good at chemistry.