So, for something light on the last day of the decade during which we have said "two thousand one" and "two thousand nine" and so on, even though we say "ten sixty six" when referring to the date of the Norman conquest of England. Allow me to define "syllabic efficiency" as saying something with the fewest syllables.
During this still nameless decade it has been of equal syllabic efficiency to say "two thousand one" versus "twenty oh one," which was the alternative nobody ever did, probably because since 1968, if not earlier, we had been saying "Two Thousand One: A Space Odyssey" for the book/movie by Arthur C. Clarke, which put us into a path dependence favoring saying "two thousand." Now we are at the potential switch point where it would be more syllabically efficient from tomorrow on to say "twenty..." rather than "two thousand..." by one syllable, because there is no more need to say that "oh" that nobody said anyway. In listening I have heard a split in speaking of next year, with some people saying "twenty ten" and some saying "two thousand ten." Which will it be, folks? Will syllabic efficiency (and the practice prior to this century) win out, or will be stuck with syllabic inefficiency due to a path dependence that Arthur C. Clarke bequeathed to us?