I figured Sunday would be a day to read stories on the 10th anniversary of the 9/11 attacks with a lump in my throat, then hug my daughter and my wife. (That beautiful September Tuesday remains the second-worst day of my life, surpassed only by the Friday in 1999 when my dad keeled over from a heart attack.) Instead, I spent much of the morning glued to Twitter.

I blame one person for that. Journalism professor and media critic Jeff Jarvis got up early to post a long series of tweets, synced to his timeline that morning–getting on the PATH train in New Jersey, exiting the World Trade Center just after the first plane struck, everything that happened after–that brought back the day with a grim urgency. A few examples:

Jarvis continued, recounting the second plane’s impact, being unable to see anything after the collapse of the South Tower and his subsequent wandering throughout Manhattan. But then he hit Twitter’s “rate limit,” silencing his account. He briefly resumed posting on Google+ until friends with connections at Twitter got his account freed up, allowing him to resume his story to its end–a reunion with his family at home.

Afterwards, Storify user Mary Bjorneby used that site to archive all of Jarvis’s tweets, start to finish–without most of his replies to people who offered thanks or inexplicable insults over his wasting their time. (He was right to curse them out. If somebody bores you on Twitter, unfollowing them will suffice.)

Other people had the same idea. Somebody else thought to set up a Twitter account, @UAFlt93, to relate the story of how the passengers on that flight fought back. A few news organizations provided live reenactments of their own–although the Guardian brought its own exercise to a halt after readers complained.

It is all compelling, upsetting reading. It makes one wonder what Twitter and Facebook would be like on a day like 9/11. May we never find out.

I didn’t think to do any such reenactment myself–I had to pack for my flight to San Francisco. (Odd timing? No. One way to honor the day is to fly without fear.) But late Saturday, I did share my own recollections of the day–repeating much of the details from the e-mail I posted here back in May, but with more about what it was like in the newsroom–on a private Facebook group for Washington Post alumni. Here it is:

When I woke up on 9/11, I must have been thinking about the big story in technology that week: the impending arrival of Windows XP. Then Bob Edwards, sounding somewhat quizzical, reported that “a twin-engine plane” had struck the World Trade Center. After the magnitude of the day’s horror had begun to materialize, I’m ashamed to admit that my first instinct was to work from home and stay out of everybody else’s way.

But Jackie Jones reached me on the phone, asked me to check out a report that a building in Rosslyn had been hit, and instructed me to head into the office. I got on my bike, thinking that Metro might not stay open for long, and was stunned to see the crowds marching out of D.C. I saw there was no room left on the sidewalk of Key Bridge–then eyed the towering cloud of black smoke rising over the Pentagon.

The day in the office was increasingly surrealistic. I somehow had the idea stuck in my thick head that I could still write an XP review and sent out some queries to the relevant flacks, even as I was collecting quotes from friends of friends in Manhattan via instant messaging to funnel to the reporters doing the real work. I also somehow thought it necessary to run downstairs to make sure that my bike was still locked to the rack on 15th Street, which allowed me to see the crowds that had gathered to buy our extra. On one of those rides down the elevator, Kathleen Day broke down in tears, saying that she couldn’t get over how many of the people she’d talked to at Cantor Fitzgerald for stories had died.

I rode home in a strangely silent city, without the usual accompaniment of planes on their approaches to National Airport. I wrote an e-mail to a mailing list for other Internet journalists that began: “I just had to turn off the TV. I can’t stand to watch the clips of the plane crashing into the building anymore–I keep hoping the jet will miss, but it never does.”

The next day, one of my freelance contributors wrote that his older sister had been a flight attendant on AA 11. I told my editor that I had been delusional to think that I could write about a new operating system, then hammered out an essay about how the Internet had provided my only way to communicate with friends in NYC and elsewhere.