KEY POINTS:
They are a diverse bunch, Barack Obama's nascent army. The greatest day in his life was also hugely important to the people linked to himself and each other through their admiration for the new President and his vision.
It's a wi-fi connection that lights as a young white woman rolls the words "President Barack Hussein Obama" on her tongue to savour the sheer improbability of it all as crowds drift from the Capitol's west lawns.
It's there when a young African-American man talks Obama up as the height of cool to his friend on his cellphone as people spread slowly north of Massachusetts Avenue.
It's there when a young Asian-American man, having spent hours in the Mall, talks excitedly about wanting to see news coverage of it, to drink it in again.
Obama has been working away for some time on a broad theme of cultural change through a revival of positive values and a more tolerant way of relating. On his train journey to Washington he said there should be "not just an appeal to our easy instincts but to our better angels".
It's a lofty goal but who can argue against a man who can inspire millions, just in one town.
Obama's supporters, and the way they have made this inauguration such a success, are the best poster children for this cultural change.
In the past few days rock, pop, rap and country fans milled together at a concert at the Lincoln Memorial. There, as on subsequent days, hundreds of thousands of people have dealt with the pressures of their congregation with good-natured patience and tolerance.
Yesterday was the biggest test of all, and passed easily.
"No problems, no incidents, no arrests, no fooling," Traci Hughes, a spokeswoman for the Secret Service, told the New York Times.
It started early.
At 5.30am with the only light thrown by street lamps, the pathways were busy enough for 5.30pm.
By 8am when gates opened the crowds were huge. The Mall, in fact the entire stretch of grass from the Capitol's Reflecting Pool to the Lincoln Memorial, was open to non-ticket holders and was crawling with people.
The chill was so pervasive, television reported a number of people were treated for hypothermia. Inside the fenced area, what little sunlight there was danced on a solitary American flag flapping from a top balcony. Ushers, some in navy blue and others in black with white hats, braid and belts, showed ticket holders to their seats.
Obama was introduced when he arrived as "Barack H. Obama" but took the slightly fumbled oath with his full name on Abraham Lincoln's old Bible. After his speech, Obama and George W. Bush walked to the East Front of the Capitol where a helicopter took the former President and his wife, Laura, to catch a flight to Texas. On the ground some departing people cheered and waved as they saw the helicopter fly away.
Hours after his address, Obama walked with wife Michelle on Pennsylvania Avenue to wave at the crowds. They watched marching bands parade.
His address was a battle cry for a new "era of responsibility" to beat back America's ills "in the winter of our hardship".
Striding confidently into the Capitol to finally - officially - become the 44th President after weeks of de facto leadership, Obama pounded on his themes with gusto.
On the bitterly cold morning, he received the warmest possible welcome from the crowd. A wrinkling red from many enthusiastically waving US flags stretched as far as the eye could see.
If the booming chants of "Obama" didn't quite gain a roll on it was probably more due to chattering teeth and shivering bodies than anything else. The celebrations were later muted somewhat by the collapse of Senator Ted Kennedy at the inauguration luncheon. Kennedy, who was hospitalised, earlier received a big cheer from the crowd when he was shown on giant screens arriving for the event.
The challenges may be great, Obama told his followers, but they will be met. "We have chosen hope over fear."
Obama cast current difficulties - a recession, two wars - as part of a long struggle for betterment, pointing out that those who had gone before had struggled and sacrificed "so we could have a better life ... this is the journey we continue today."
Part cajoling, part stern master, Obama warned that there were no excuses: "Greatness must be earned... Our capacity remains undiminished... We must pick ourselves up."
Obama had a message for terrorists - "you cannot outlast us and we will defeat you" - and implicitly attacked the policies of the man he had just replaced, George W. Bush.
He spoke of "our collective failure to prepare for the future" and emphatically declared that "we are ready to lead once more". He told the Muslim world that he sought a new relationship "based on mutual interest and mutual respect.
"As for our common defence, we reject as false the choice between our safety and our ideals. Our Founding Fathers, faced with perils we can scarcely imagine, drafted a charter to assure the rule of law and the rights of man, a charter expanded by the blood of generations.
"Those ideals still light the world, and we will not give them up for expedience's sake."
But his chief goal was to insist that the "spirit of service must inhabit us all". The challenges may be new and the instruments used to tackle them may be new, but values such as kindness, selflessness, honesty and hard work are the "old quiet force of progress".
The crowd started drifting away once Obama had finished. But the ground was so thick with people, progress was an inch at a time. Still people stayed patient and kept their enjoyment in the day intact.
For once, this time, the better angels had the skies to themselves.
JOKES TAKEN IN GOOD SPIRIT
The Reverend Joseph E. Lowery, the 87-year-old Methodist civil rights icon who gave the benediction, began with the third verse of Lift Every Voice and Sing, a hymn known as the "black national anthem." Several sentences later, he repeated a phrase from another hymn, He's Got the Whole World in His Hands.
Then he cracked a few jokes: "We ask you to help us work for that day when black will not be asked to get back, when brown can stick around [laughter], when yellow will be mellow [more laughter], when the red man can get ahead, [more laughter], and when white will embrace what is right."
Then, paraphrasing Micah 6:8, he ended with a hearkening to revival time. "Let all who do justice and love mercy say amen," he said, and the crowd yelled back, "Amen!" He repeated the "amens" and left the podium to cheers.
