Example: Pedants know that the third millennium AD started in the year 2001. That's because the years 1-1000 were the first millennium, and 1001-2000 were the second. That makes 2001-3000 the third.
Some other folks heard this, and -- not quite understanding it -- extrapolated that this means that the new decade after the naughties (or whatever cutesy term you prefer to use to refer the period that ended with December 31, 2009) does not start until 2011. Despite the facts that A) any ten years form a decade, regardless of when they start, and B) the decades in question are specifically identified by the second-to-last digit of the year (the 80's, the 90's, the 00's, etc.).
It is true that the two hundred and second decade AD hasn't started yet (and won't start until 2011). But how many people actually care about the two hundred and second decade AD? The rest of us are still busy trying to come up with the correct cutesy name for the 2010's.
Does anyone have any other good examples of cargo cult pedantry?
