It's because in conversation, someone usually says (using this example), "August the twenty-eighth, two thousand and fourteen," or some slight variant of that. In writing this was usually rendered as Aug 28, 2014; the format used online keeps the sequence and simply converts the month into a number.
It's a NW thing. 4E does have damage type resistances, although it isn't automatically the case that something is immune just because it uses a given damage type, and resistance is more common than outright immunity.