Justine Sacco’s saga has been reported, analyzed and dissected more than most breaking news stories. While there is no excusing the message she tweeted, the reaction has far exceeded her transgression. Steve Martin (who himself apologized recently for a racially-insensitive tweet) once proposed the death penalty for parking violations. Death threats for an insensitive tweet seems a lot like that.

(If you’re scratching your head wondering who Justine Sacco is, you can get up to speed with this Los Angeles Times coverage.)

People who know Sacco don’t believe she’s racist. Writing in the Huffington Post, journalist Jeff Bercovici praises Sacco’s abilities as a corporate communicator, “the kind of flack who’s all too rare, the kind who doesn’t stop being a person when she badges in for the day at work.” He recounts a conversation in which Sacco—still working out Twitter’s nuances—voiced her preference for tweets"that were just a little bit risque or outrageous.” Applying that predilection to her own account has now cost Sacco her job and made her a global pariah.

While I found her tweet as offensive as anyone else, I can’t help but feel bad for her. Peter Shankman has even suggested that she’d be a great hire right now. In addition to being a terrific, talented communicator, she is more sensitive than just about anybody to the behaviors in social media that can get you in trouble. Besides, he says, everybody deserves a second chance.

While coverage of Sacco’s transgression and the consequences she has endured has been more than ample, there are two lessons communicators should draw from it.

Lesson #1: Social networks are public

Much has been made of the fact that Sacco had only about 200 Twitter followers and no doubt felt her tweet would be seen only by her friends and colleagues who got her brand of humor. One conservative blogger even suggests Buzzfeed—where Sacco’s tweet was first reported—may have had some hidden agenda in exposing the tweet to the world.

Why an obscure communicator from a company most people had never heard of was targeted for such excoriation is irrelevant, as is the fact that Twitter, Facebook and other channels are littered with thousands of vile and hateful messages that make Sacco’s look tame by comparison. The only issue that matters is the fact that tweets are public. Even if only 10 people follow you, your tweet is in the public stream, discoverable by search, and embed-ready. If you don’t want the world seeing it, don’t tweet it. Period.

Lesson #2: Lesson #1 is why ephemeral and private messaging apps are a big deal

Talk to most people about Snapchat and, if they’ve heard of it at all, they dismiss it as a tool for sexting. While sexting undoubtedly goes on via Snapchat, that’s not the reason most people use it. The young demographic that has embraced Snapchat got tired of their messages to friends being seen—sometimes long after they were posted—by prospective employers, Aunt Tilly, and self-righteous bystanders. Snapchat was a safe harbor, a tool they could use to have their genuine conversations without the risk of people who were not intended recipients dredging up their messages.

Snapchat has competition, too, in the form of upstarts like Leo, which aims to create a new kind of conversation space with messages that disappear a few seconds after you read them, just as they do in face-to-face discussions. Where Snapchat is focused on images, Leo is more interested in the messages themselves, although video and images are part of the mix. Any participant can invite somebody else to join an existing conversation mid-stream, and he’ll have to pick up on what’s going on just like somebody joining a group of people in the middle of a discussion at a party.

In addition to the ephemeral conversation tools, hundreds of millions of people have shifted their online messaging habits away from social networks like Facebook and Twitter to “over-the-top” mobile messaging apps like WhatsApp (which recently passed 400 million active monthly users; in its SEC disclosures, Twitter numbered its monthly active users at 232 million), WeChat, Kakao Talk, Kik, Line and a host of others. While the messages don’t disappear, neither are they public. Only the individuals or groups with whom you want to communicate can see your messages.

While these tools have been adopted primarily by younger users, the Sacco affair will most likely inspire a surge of downloads by people who suddenly realize they need to do something different than Twitter and Facebook if they want to have private conversations. As adoption of private and ephemeral messaging tools surges, communicators will have to figure out how these platforms can fit into a marketing or communication plan. For example, you can’t enlist followers to a brand page on Leo, but you could invite subject matter experts and customer service representatives to get accounts and make themselves available for conversations about product or service issues.

The suffering Justine Sacco is experiencing—which is out of all proportion to her crime—won’t be in vain if brands learn from it. If we don’t, it’ll just be one more source of online titillation, a footnote in the history of social media missteps.

One final note: If you’re looking for a PR professional, I concur with Peter Shankman. A flack who is well-liked by the journalists she pitches is a rare commodity. Sacco would be a great hire.