Lots of readers objected to my assertion that the decade is not ending tonight. One sent over this excellent discussion of when the decade ends and when it begins — and why, he argues, my conclusion is wrong (I am right when it comes to millennia and centuries, but counting “decades” is really informal).

Interesting point he concedes: If we count decades they way most readers say we should (ie, ending tonight) then this means the first decade in our calendar only had nine years: AD 1–9.