It began with the tease of a midnight catastrophe, Y2K, that didn't amount to much.
But lurking in this jittery first decade of the new millennium was a real catastrophe, 9/11, that would shake the nation to its core - and then a global economic shift at the decade's close that many historians think has left the United States with diminished global standing.
"We're going back to historical norm," said the economic historian Stephen Davies, author of a recently completed history of the world since 1250. "For most of its history, the United States has become more central and more powerful in the world economy. I suspect it's entering a period of relative decline now."
A fitting end, perhaps, for a melancholy decade in which privacy took a hit, the economy ruptured, unemployment surged, intimate details became something shared on Facebook before breakfast with people you casually know, lag time became an endangered concept, and your pocket held a device constantly updating, searching, interrupting, and distracting.
Historic milestones were dizzying and confusing: a presidential election decided by the Supreme Court, an attack by terrorists on American soil, a war on two fronts, the unraveling of Enron and Madoff, a debate over torture, an entire city nearly lost in a hurricane, and, by decade's end, a black man elected president.
Historian James W. Hilty of Temple University Ambler calls the decade one of "comeuppance and squandering," and thinks the 2000s may be "the most important 10 years of American history" since the 1930s.
"America in both decades experienced great highs and abject lows," he said. "Both were periods of unprecedented wealth and prosperity followed by descent into financial abyss. It's a decade when we've had a reckoning."
In Philadelphia, there was uncharacteristic triumph. The city's sports fans were remade in the eyes of the world, portrayed as winners, as tender dads hugging their foul-ball-tossing-back daughters. The Vet was vanquished, replaced by the Linc and the Bank. There are fans born in the 2Ks who do not remember the Phillies as losers.
And even as the city struggled under a tightening economic noose, Center City continued a revival that spread to neighborhoods to the northeast and south, which became hipper, artier, foodier, and more inclined to attract immigrants from Brooklyn.
Comcast built a gleaming tower and, with the purchase of NBC Universal at decade's end, seemed poised to increase its influence in our living rooms and laptops.
The FBI planted a bug in the mayor's office, Miss America hightailed it to Vegas, casino gambling spread to Pennsylvania, Vince Fumo was toppled.
The decade's nearly 3,000 losses from 9/11, and current toll of 5,288 from the Iraq and Afghan wars, took a heavy toll locally, from the prominent - John P. O'Neil, an Atlantic City native son who was head of security at the World Trade Center, and LeRoy Wilton Homer Jr., 36, of Marlton, a pilot on United Flight 93, which crashed in Shanksville, Pa. - to the dutiful: 233 soldiers from Pennsylvania and 93 from New Jersey.
Only four states - California, Texas, New York, and Florida - had more casualties than Pennsylvania. The flag-draped coffins were sent home to the nation's military mortuary in Dover, Del., mostly out of public view.
How, then, to make sense of the aughts? How to define a decade that nobody knows what to call? A decade of distractions and tragedy, technology and trivialities, anxiety and war; of George W. Bush, Dick Cheney, and Barack Obama; of Abu Ghraib and Sarah Palin, Jon & Kate and American Idol; a decade when reality was something faked for ratings, stripper culture went oddly mainstream, and being plucked from obscurity afflicted both television and politics.
For historians, the convulsing of the economy trumps all else - even the jolt of 9/11, the election of Obama, or, in the most spectacular implosion in popular culture in a decade full of them, the unraveling of Tiger Woods (or, for that matter, Jim McGreevey).
"The really fundamental issue is the economy, in particular the confluence of irrational exuberance, the bubble, rising inequality, the massive collapse," said University of Pennsylvania historian Thomas J. Sugrue.
Next, Sugrue ranks the foreign policy shift after 9/11 toward intervention - "the sense of crisis and emergency that's become the justification for massive military intervention in the Middle East. . . . Everything else is a footnote," he said, including Obama's election. "We will only fully understand 10, 20 years from now whether Obama is a decisive break. He looks a lot like both Clinton and Bush. There's no evidence right now that his election has had any significant effect on the shape of race and racial inequality in the U.S."
Will history paint Obama as less than transformative, a letdown bookend with Y2K, both heralded as momentous shifts but in the end meaning less than anticipated? "There's no discounting the symbolic importance of his election," said the Ohio State University historian Kevin Boyle. "There's been a great sea change with Americans' attitude about race. But the structures of race have become even more entrenched."
To illustrate what a difference a decade makes, Temple's Hilty noted that while the country now carries a $12 trillion debt, "the key issue of the election of 2000 [was] how to spend the surplus. We lost all advantage."
The historian Michael Bernstein, provost of Tulane University in post-Katrina New Orleans, sees "a new gilded age": a housing boom and bust, fat-cat bankers, progress choked by an ethos of politics over all, the emergence of a strengthened European Union whose gross domestic product exceeds that of the United States, a shift in financial dominance to China. "As you look back at this decade, the inequality parameters worsened," he said.
Houston A. Baker Jr., a scholar of African American literature and author of Betrayal: How Black Intellectuals Have Abandoned the Ideals of the Civil Rights Era, said problems in the black community dwarf Obama's achievement. "Symbolically, this was colossal," he said. "But it's not even the best of times and the worst of times. It's just the worst of times. There are 2.5 million people in prison. We manage the dissidents, the rabble, the problem people, by putting them in prison."
The reach of information this decade was both liberating and humbling. The novelist Jonathan Lethem, in an interview on Salon.com, put it this way: "Everyone's a master of secret knowledge now."
Much of the mobile and digital revolution was unimaginable even a few years ago. As the TV host Stephen Colbert said recently: "My father came to this country without a pocket!"
In the 2000s, people became their own PR firms, authors of semiautobiographical novels-in-progress, encapsulators of irony, manipulators of reality. People and things once thought lost were found. Only heartbreak and death truly took anyone away.
We were all Maxwell Smarts, talking into our shoes, Bruce Waynes leading parallel lives, one in front of us, one in the ether. By the end of the decade, there was an iPhone app to brighten teeth in photos. Reality merged with reality TV; even the White House was punked. While Obama bailed out the banks, Colbert and his viewers bailed out the Olympic speed-skating team.
Irony did not die after 9/11, it just became the tool of the Twittering masses. As we roll over from the fearful 2Ks into the 2K-tens, we're drowning in it. Everyone's a master of snark. Text trumped voice by decade's end, but text on paper - and news on print - seemed endangered. Annoyingly upbeat updates once limited to Christmas letters get meted out in real drip-drip-drip time. Call it the Wait-why-aren't-I-that-happy? decade. Or the Am-I-happy-now?-How-about-now? decade. Or maybe all the outer peace is from antidepressants. As cited by Anna Jane Grossman in Obsolete: An Encyclopedia of Once-Common Things Passing Us By, by mid-decade more money was being spent on Zoloft than on Tide. (She says sadness is obsolete, or at least optional.)
"We've never in history experienced technology shifting at this kind of rate," said Grossman, who also cites "getting lost" as obsolete, physically and existentially. "The last decade has given a lot of people whiplash."
Lauren Sessions, research fellow with the Pew Research Center's Internet and American Life Project, said Internet use changed from a way to connect with those far away to a constant way to communicate with those near and far. Rather than being isolated, "Internet users have both larger and more diverse social networks."
By the end of the aughts, the 2Ks, the 2000s, the whatever-you-want-to-call-it decade of uneasiness, so much has arrived at our fingertips, on the tip of our thumbs rolling anxiously over the buzzing phones in our pockets: friends, "friends," music, news, books, research, gossip, answers, obligations, annoyances, sex, secrets, the ability to tell the world, the facility to connect with a lover (or, like Tiger, 14), the cozy reemergence of your grade school playmates, the temptation to define and redefine yourself, to narrate your best and worst self, to update.
But while so much was newly in our pockets this decade, so much else remained out of reach: jobs, economic stability, credit, mortgages, the notion that prosperity is a place you reach and remain. As they used to say on the Internet, not so much.
In the waning days of the decade, even the early innovations of the warp-speeded aughts - the iPod, born in 2001 and still quaintly storing music on a hard drive - seemed headed for an obsolescence heap that has become a (not-so-green) landfill this decade: Apple bought LaLa, which keeps tunes online, or "in the cloud," where in the next decade your hopes and your dreams, and your music tracks, may all reside.
And onward we march, slouching, as they say, toward another decade we don't yet know what to call.