Warning signs dot the hallways of Mounds View schools, reminding students to T.H.I.N.K. before they post.

Is it True, that thing you're about to put out on social media for the world to see? Is it Helpful? Is it Inspiring? Is it Necessary? Is it Kind? Is it going to get you and everyone around you fired, Roseanne?

That last line is not on the poster, because that line is not Kind. Maybe they should hang some of those posters outside the schools, too.

This has been a week of teachable moments on social media.

Roseanne Barr went off on a show-killing tweetstorm of racism and rage.

Bryan Colangelo, general manager of the Philadelphia 76ers, got caught juggling what seems to be a stable of phony Twitter accounts he used to attack his players, flatter himself and defend his indefensibly large shirt collars.

Samantha Bee had to tweet an apology on social media for calling Ivanka Trump the C-word in the actual media.

Everything you need to know about online decency fits on a poster. If you have additional questions, high schoolers from the Mounds View Public Schools produced a series of instructional videos a few years ago, outlining the risks of online awfulness and the rewards of not being awful online.

Roseanne did not T.H.I.N.K. before she posted. Now 200 people are out of a job, thousands of people can't watch the show they enjoyed, and I have to stop here to point out that it is never, ever OK to compare African-Americans to primates. That's the oldest, most racist card in the Terrible White People deck, and you know it. No, it doesn't matter if somebody else compared the president to an orangutan. I am so disappointed in you right now.

Here. The Irondale and Mounds View high schoolers explain it better than I can.

"Everyone's Watching," the Irondale video, opens on a disgruntled student athlete tweeting that his #clueless lacrosse coach isn't playing him enough. Later, he watches in horror as the tweet is picked up on the evening news. A young musician's snarky Facebook post about how "my band will never go to State if Amber keeps messing up the song" makes the student newspaper. Finally, a mean Snapchat video of Brooke ("WORST player ever!") missing a shot at basketball practice ends up airing on talk radio.

A warning fills the screen: "Sharing it on social media is like sharing it with the world."

"These are good kids," said Jim Galvin, activities director at Mounds View High School, who enforces the school's policy that the things you post online follow you back to the real world. "Good kids do make mistakes [and] those mistakes can be very costly to their futures."

So far, he said, he hasn't had to bench any of his players as a consequence for something they did online.

The kids get it. They grew up in this digital briar patch. I have nieces in grade school who can crack my pass code and reprogram Siri to call me Poo-Poo Head in less time than it takes me to write them out of my will.

It's the grown-ups who can't seem to figure out that their clicks have consequences. An Indiana school board president resigned Thursday over a "We stand with Roseanne" post she shared on Facebook. She said she hadn't read the racist tweet that got Roseanne fired, or any of the racist tweets before that one.

Don't think it couldn't happen to you. We're all just a tweet away from posting something so awful it's either going to get us fired or elected.

I use social media and I adore social media. The people I meet on Twitter are sharp and hilarious and my primary source for breaking news and cat videos.

I can't say the same for myself, because I've reviewed a decade's worth of my social media posts and concluded that I T.H.I.N.K. in almost none of them.

The true tweets aren't kind. The necessary tweets aren't inspiring.

And almost nothing I tweet is helpful, except in late August, when I will live-tweet the Minnesota State Fair and produce the purest posts about Pronto Pups you will ever see.

In the spirit of full disclosure, I also once tweeted a screenshot from my home computer, then deleted it, screaming, when I realized it showed the tab to a hilariously mean "Fifty Shades of Grey" book review I'd been reading on another screen. (I enjoy reading savage "Fifty Shades of Grey" reviews. I won't apologize for that.)

So T.H.I.N.K. might be too high a bar for me. Most days, I'd settle for Accurate with a side of Funny.

When I'm debating whether to hit send on an iffy post, I run through a different checklist: N.A.H.H.H.

N: NO! Did you even watch the Mounds View videos?

A : Am I going to have to have to slap the phone out of my own hands?

HHH: What would Hubert H. Humphrey tweet? I have no idea. Let's go to the Minnesota Historical Society and do a deep dive in the stacks until the urge to tweet passes.

jennifer.brooks@startribune.com • 612-673-4008

Follow Jennifer on Twitter: @stribrooks