Sorry, no quick summary available (unless if you’d stick to your sugestion: narcissism and… calendars.)
Anyway, I’d strongly the full version.
For better and for (not much) worse, it’s all in comments sectoins, and almost all in off-topic mode.

Part 1 (Intro): The two last comments on Arne’s “Computer Skeptic No More” (no need to reed the column itself for this purpose);

Part 2: Arne+Castro comments on this very Arne’s article (beggining with “Castro on December 27th, 2009 9:42 pm”);

Appendix (incredible bonus track): Sumit Balan, Castro and Amos comments (1+2+1) on the “Grischuk & Galliamova Champions” article.

I know, one hardly wants to go such a way, but believe me, it worths to do all that reading!

7. The “Gregorian Calendar” was not “the original”! What a confusion!
The Gregorian operation just dealt with the accuracy of it, nothing else (and dealt very engeniously, BTW). It has NOTHING to do with what we’re talking here. The meaning of the (this) calendar stayed as before (and will remain forever, no matter what confusions are tried. It’s COUNTING time. THAT is “the logic of it”.

8. “…the astronomical year. In fact, the ISO 8601 standard of recording time assumes this practice (with a year 0)”
In fact, as I said, that is done with certain specific scientific goals. That is not meant to substitute any “old” system! BTW, I repeat, our calendar is not “old” in that sense. What makes sense to MARK is (decimal) portions of time PASSED over certain event.
0, as an unit (also then being imposible to consider in the past), can nothing but deny that concept! (It can serve other noble concepts, but those are as strange to this as it would be strange to count your own first year of existence as “zero”).

9. Of course I’m not an “Arthur C. Clarke”, but this brilliant man made the CLASSIC MISTAKE. (a most basic one, I must say, but human isn’t perfect) In fact, I’m glad you brought that here! His analogy is good to refute him!
The “scale on your grocer’s weighing machine”, as your thermometer, as your velocimeter (and so on) begin at (or have) zero but AS A MARK, AS AN INSTANT, NOT AS AN UNIT, because otherwise you couldn’t “be happy when he claimed he’d sold you 10 kg of tea”! That’s because! Having zero as an unit would precisely falsify the thing we wanted to be less falsified! The counting, the real measure.

10. “This is of course when the 9 becomes a 0 because psychologically this change is much more dramatic than from 0 to 1.”
This is the ONLY apreciatable argument! That and the number of believers, maybe!
But I’m sure everyone will agree (after some time pondering, maybe?) that this one argument has one fatal defect. It is profoundly anti-scientific. It’s, as I said, a very understandable confusion and refuge, similar to that of the people afraid to get into a car, or satisfied with the Earth being flat. There are contextes where (and people for whom) this notions can even be useful, and reasuring some basic PSYCOLOGICAL situations.
If they want that, let them have it! I never said that religion should be banned!
One thing is for sure: Passing that fear and ignorance wall, even they would benefit!

11. Ok, and what a releaf! By your definition, I’m really not that pedant, not even by your (anounced, but for others!) standards!

1. To begin with, NO, you didn’t even try to answer before;

2. NO, you didn’t begin all the issue (on the column “Computer Skeptic”) by being any ponderous about the remark I made, just tried to ridicularise strait away, not to mention “any” reason I could have, and not to mention that OF COURSE you wouldn’t allow any “there’s more than one way to look at the issue”, as you claimed after.

3. My formation is on Mathematics, so again you go very wrong thinking I could be confused about ordinals and cardinals, on the calendar. My greatest love on Maths lyes precisely on the foundations of it.

4. Our calendar is not a “fuzzy concept”, Arne, unless we want it to be.
You say “your definition of millennia and decennia consists of using ordinal numbering, and mine of cardinal numbering”. This is wrong! You don’t obtain different results in years, millenia, decenia, whatever years related, by means of thinking which order something comes, or how many time periods are we counting.

5. Of course any counting of units that includes 0 as an unit yelds 10 units when we gether 0 to 9. And a dozen is yeld at 11, of course. But as I said (on my VERY first post on this) (and you couldn’t do more than confirm!), for the calendar that is only posible with a modern and artificial time counting system. (BTW, Next time someone asks your age, or at what age one should comemorate two decenia, don’t answer rushily! )

6. There is no such thing as an “old way” (in which, you imply, 1973 would mean something strange), and a “modern way” (in which “1973″ means 1973). That’s pure fantasy! 1973 means the 1973th year, whatever turns you try! This is the ordinal view, as well as the cardinal view! 1973 is the year coming after 1972, and there are 1973 years completed when 1974 begins.
That is as “modern” as could be, because we’re talking about THIS counting system, NOT some other created just for certain goals.
Sure, maybe the counting was somewhere in the past slightly confused, and Jesus really was born some years later or earlier, but the thing the calendar is to is to mark how many time passed since his birth. Pedantic is otherwise.