It is true that during the year 2000 many meetings of world leaders, etc., were held … with the aim of solving the major issues the world faced. One widely held belief was that computers would ensure that there would no longer be periodic financial/economic booms and busts. The year 2000 was enthusiastically promoted as the start of a new age of prosperity and happiness for all mankind.
I think that he means that for most of us non-religious types, the number 2000 is just the way we count years from an arbitrary point in time, and therefore have no problem with there being a year zero instead of a 1 b.c.
And what terrible thing has happened as a result?
What terrible thing would result if a lot people thought Lincoln was the first US President?
But a person saying that or that the millennium began in 2000 is still “uninformed”, to put it mildly.
It helps if people with responsibility aren’t idiots.
The millennium is a metaphor, and metaphors are subjective. They mean whatever people think they mean.
Of course there was a Year 1. There may not have been banks around giving out calendars with a great big “1” on it, but so what? AD 1 or 1 CE is a specific year in history, and 2001 was 2000 years after it and thus the beginning of the 21st century of the Common Era.
The UK national newspapers will probably play this for all tney can. Were you born on Jan 1st 2000? Then that means you’re really special now that you’ve become an adult. How are you gonna react to those who tell you otherwise … that everybody born in 2000 is a 20th century “product”.
Bleh. That’s mathematically hideous. I’ll pass.
Sure, but of all the different ways that people can be wrong, this one doesn’t rank very high on the catastrophe scale.
Counterpoint: 2000 is a round number, and round numbers are cooler. Rule of Cool takes precedence.
Then just say that! Why confuse things by saying it’s the start of THE millennium???
It may be cool to turn 21 but you don’t say “I’ve started my third decade.”
1st January 2000 was the practical start to the 21st century. The weight of public opinion has already decided it is so.
Were you born on the first of January 2000? then you will be regarded as having being born in the 21st century. When we talk about meaningful decades and mention things that happened in “the sixties” we include stuff that happened in 1960 and don’t include stuff that happened in 1970.
So the concept of the 21st century is as much a social construct as a mathematical one and society always wins.
In my own mental calendar, the Seldonian, there was a year 0 and therefore 2000-01-01 was the first day of the century. But which century? The 20th of course. For just as there was a year 0, there was a zeroth decade, a zeroth century and a zeroth millennium. So we are now about to start the 18th year of the first decade of the 20th century or second millennium.
I notice that the OP has not acknowledged his or her error, although he/she did provide an excellent example of Gaudere’s Law.
I’m getting a little fuzzy here. Is it the contention of some people in this thread that the 21st century actually started in 2001, rather than the year 2000? If so, how does that work, exactly?
And, indeed, what possible difference could it make?
Actually I don’t disagree with that – with the idea that Jan 1, 2000 marked an important symbolic milestone. Certainly many people responsible for computer systems, especially in the financial industry, thought so. It would certainly have been amusing if financial calculations has taken “00” to be the year “1900” instead of “2000”, and my checkbooks with “19” preprinted in the date field were suddenly not as useful as they once were. All those things are true. Those who wanted to celebrate like mad on Jan 1, 2000 could do so with my blessings and much justification. Just don’t say there was never a year “1”, and don’t call 2000 the beginning of the 21st century. That’s not how counting works. It’s like calling the 1900s the “nineteenth century” because it begins with “19”.
Sure, in the unusual sense of the word “practical” meaning “wrong”. 
Somewhat less facetiously, it’s a symbolic milestone but it is NOT, in fact, the 21st century of the Common Era in the Julian calendar, a fact which can be determined by the simple expedient of counting.
Actually, no. It depends. If we’re looking at an era as defined by social and cultural events, “the sixties” was a social phenomenon that started around 1963 or 64 and lasted well into the 70s. Of course if one is talking about calendar years, and going through history on a year-by-year basis, then “the sixties” corresponds to calendar numbers by definition, which is not very interesting and is not the argument here. But again, if we’re counting decades, or counting centuries, then we have to be conscious of starting points or we’re going to be mathematically, factually wrong.
It’s the kind of silly argument that one can spend days getting all pedantically worked up about. It’s what the Internet is for! 
A few days into 2000 I placed a large sandwich board outside Waterstones bookshop in Hampstead, London which read: WE ARE STILL IN THE 20TH CENTURY … and watched how people reacted to it. Everybody looked “confused” … the newspaper front pages had declared that we were now in the 21st century. I mean … if it’s on the front page of the newspapers it MUST be true, eh? The idea that the media would deliberately play mind games with the populace … “brainwash” people into believing something tbat is not true … is more than people’s minds could cope with. People did not decide for themselves that the year 2000 was the first year of the 21st centtury … their thinking was overwhelmed by what was coming from the media.
Makes sense. Obviously the media needed to brainwash people into not accepting Gregorian numbering in order to- in order to…
Umm… Nope, my mind can’t cope with this.