Is 9/11 fair game for humor?

Can there be anything funny about nearly 3,000 people dying in a multi-pronged attack on the United States involving jets flying into buildings and a plane crashing in Pennsylvania?

There weren't many laughs after the actual event. Americans and US comedians went silent, numb. Late night shows took a hiatus. When they returned, it was with a somber tone. The Daily Show with Jon Stewart was one of the last to resume, on Sept. 20, 2001. After expressing his own and everyone else's pain, Stewart said something that got a laugh.

There were early attempts at 9/11 humor that flopped. At a roast of Hugh Hefner in New York on Sept. 29, 2001, comedian Gilbert Gottfried joked: "I have to leave early tonight. I have to fly to LA but I couldn't get a direct flight. I have to make a stop at the Empire State Building." People gasped and booed and one man yelled out, "Too soon!"

In 2011, Gottfried was fired by AFLAC (he was the duck voice) after tweeting tasteless jokes about the tsunami that devastated Japan.

A famous 9/11 humor success came from The Onion just two weeks after the attack, on Sept. 26, 2001. The fake news site devoted the entire issue to 9/11. The headline (asterisks ours): "Holy F*cking Sh*t: Attack on America." Laugh-out-loud stories included "Hijackers Surprised To Find Selves In Hell" and "God Angrily Clarifies 'Don't Kill' Rule."

In an article titled "U.S. Vows To Defeat Whoever It Is We're At War With," then-President George W. Bush speaks from the Oval Office:

"America's enemy, be it Osama bin Laden, Saddam Hussein, the Taliban, a multinational coalition of terrorist organizations, any of a rogue's gallery of violent Islamic fringe groups, or an entirely different, non-Islamic aggressor we've never even heard of... be warned. The United States is preparing to strike, directly and decisively, against you, whoever you are, just as soon as we have a rough idea of your identity and a reasonably decent estimate as to where your base is located."

The Onion's master stroke was to make fun of the attackers, not the victims. In comedic circles, Osama bin Laden immediately became (and remains) a cartoon punching bag. Eventually, in many quarters, so did Islam.

Karl Sharro, a Lebanese satirist who blogs and tweets under the name Karl reMarks, says the first jokes he saw after 9/11 were by Muslims and Arabs, worried about how they'd be treated since Muslims and Arabs were behind the attack. "They were jokes like 'Oh no, you think it was hard to get a visa to the United States before, now it will be impossible!' ... And that fear of Muslims is exactly what happened."

Anti-Muslim feelings post-9/11 also ended up spawning a new brand of comedy from Muslim and Arab-Americans like Maz Jobrani, Dean Obeidalla and dozens more, whose jokes are all about being Arab and/or Muslim in a post-9/11 world.

But this many years later, there are still many lines not to be crossed. A store in San Antonio called Miracle Mattress was pilloried online just last week after promoting a "twin towers sale" — every mattress sold on Sunday, the 15th anniversary of the attacks, would be the price of a twin mattress.

At the end of the short video, staff fall screaming into two large towers of mattresses, which collapse, and the narrator says, "We'll never forget."

The ad was posted on the company's Facebook page but immediately taken down. The owner of Miracle Mattress apologized profusely, saying the video had been made and posted without the permission of management. The store has been closed indefinitely.

Two years earlier, The Onion ran a fake 9/11 anniversary promotion by the Subway fast food chain. Subway complained about it but it remains on The Onion's website.