Marketers including AT&T are getting schooled on the fact that jumping in on the social conversation around national tragedies is not the safest arena for real-time marketing.

A handful of brands are being smacked around today for posting 9/11 commemoration tweets perceived as inane at best and insensitive at worst.

AT&T received the brunt of the outrage after tweeting a picture of the beams of light shooting up from the Twin Towers site, captured in the screen of a phone that's poised to take a photo, with the text "Never Forget."

The tweet was promptly removed, and AT&T issued an apology:

We apologize to anyone who felt our post was in poor taste. The image was solely meant to pay respect to those affected by the 9/11 tragedy.

— AT&T (@ATT) September 11, 2013

While AT&T's post was the most overt as an ad, plenty of other brands -- including Waffle House, Huggies, Red Lobster, Macy's, Walgreens and White Castle, as chronicled in a series of retweets by comedian Joe Mande -- offered up sentiments of remembrance on the 12-year anniversary of the terrorist attacks.

We will always remember. http://t.co/bQs2LH4WCP

— Walgreens (@Walgreens) September 11, 2013

Hug your family. Reflect on the sunset. Look forward to the sunrise. Hold your head high. Imagine a better world. And #NeverForget 9/11/2001

— Macy's (@Macys) September 11, 2013

The Los Angeles Lakers, for one, seemed to realize they were treading on thin ice. The team posted a photo of Kobe Bryant with the hashtag #NeverForget superimposed, but quickly deleted it.

While the other 9/11-related tweets from brands didn't provoke the same negative reaction as AT&T's, they still walk a fine line in terms of relevance, according to David Berkowitz, CMO of MRY. While it would be fitting for a health care company that treats 9/11 first responders or a brand that actively runs scholarships for the children of the deceased to weigh in, trivialities like #NeverForget seem tone-deaf, he said.

"Unless you're bringing something of value, the easy thing is just to keep your mouth shut," he said.

On the other hand, brands' social channels are run by humans, and users of those products have come to expect humanity, according to Adam Kleinberg, CEO of Traction. He said that a simple "we remember" like Shutterfly posted to Twitter strikes the right chord.

Remembering 9/11. We will never forget.

— Shutterfly (@Shutterfly) September 11, 2013

"Where AT&T blew it was in being too clever and self-aggrandizing," he said.