On newspaper racks Tuesday, 9/11 was markedly absent from the front pages of the New York Times and the New York Post.

"The pain, the outrage, the loss -- these never fade," wrote the Times public editor Margaret Sullivan. "The amount of journalism, however, must."

On the 11th anniversary of a tragedy, some Americans arose not remembering.

It was another day of making coffee, packing sandwiches for kids' lunches, dropping off the dry cleaning before work. Memorial ceremonies, too, were fewer and simpler than in the past.

It is natural for time to heal. Natural, too, for people to want to move on.

But there was one place where the tragedy was hard to miss -- on social media.

Twitter, Facebook, Google Plus and Instagram did not exist 11 years ago. 9/11 did not transpire in social media real time as many news events today do. But memories of that horrific day were kept alive Tuesday via smartphone, tablets and computers.

Social media was a way for people to express their emotions when there were fewer physical ways to do so, said Robin Carey, CEO of Social Media Today.

Maybe you weren't going to the local remembrance and hear the bells toll at 8:46 a.m., the time American Airlines Flight 11 slammed into the North Tower. But you could get out your phone and tweet what you remembered about that moment.

"There's a lot of trending now on Twitter which shows it's a lot more durable than the media would believe at this point," Carey said.

Among trending topics Tuesday were WTC, 11S, Remember911, Iraq, New York City, R.I.P and Bush.

"If the public comments did not exist, then you would not have the same attention on 9/11," said Sanford Dickert, a social media technology expert.

"There are so many moments we have let go because in the mental consciousness of our society, sometimes we forget things," he said. "Social media provides the opportunity to find those issues you are concerned about."

The New York Police Department memorialized fallen officers through a Twitter campaign with the hashtag #neverforget. Each tweet linked to a poignant Facebook page about an officer. It was the social media version of a reading of names.

Some people tweeted about where they were when they first got news about the attacks.

@mikestuchbery: "This time 11 years ago I was working on a presentation for a uni English course. It never happened."

Facebook users posted photos of how Lower Manhattan looked with the Twin Towers and how it looked Tuesday morning.

Others posted sayings such as "Never Forget," and still others, their remembrances of people who perished that day.

Even politicians took a break from the campaign to offer their remembrances on Twitter. President Barack Obama (@BarackObama) tweeted: "As painful as this day is and always will be, it leaves us with the lesson that no act of terrorism can ever change what we stand for."

His rival, Mitt Romney (@MittRomney), posted: "In remembrance, let us recall what the flag symbolizes & the many who have sacrificed so that we may fly it proudly."