The death threats started rolling in as soon as a jury acquitted Casey Anthony of killing her daughter, Caylee, 2. They convicted her on charges of lying to investigators.

The court of public opinion has reached a different verdict, and Anthony may be stunned by the level of hatred she'll face once she is released this week. But the vituperative response is something we should all consider. It's a problem that goes well beyond the question of whether the jury was right.

I don't know what happened to Caylee. I don't know which of the competing claims of the prosecution and defense were high drama and half-truths dressed up to win a desired result.

But I do know this: A jury that has reasonable doubt must acquit, or our entire system of justice falls apart. And if anyone I care about is ever charged with a serious crime, I want to know that the case has to be proven. I don't want justice determined by straw poll.

How vigilante "justice" or a mob mentality betters any situation is simply beyond me.

I've been thinking about this partly because of an email I got this week. I did a blurb about Elizabeth Smart's new job commenting for ABC on missing person cases. The story contained a reference to Anthony as an example of a current high-profile case about which Smart could be asked for her thoughts.

A reader blasted its inclusion: "I think you may be underestimating this new level and type of mob activity. I am finding it increasing at an alarming rate. ... It is a phenomenon the like of which the world has never seen and I believe it is set to explode in intensity and influence."

The decision to put a sentence about Anthony in the short article, she noted, "just feeds the frenzy."

I think she's probably right. We're meaner and more opinionated than ever as a society. And social media and technology have made "going viral" a fact of life.

Google has a feature that offers suggested searches based on what's trending. A look at "death threats" brings suggestions that you look at those made against young actress Selena Gomez (who had the nerve to kiss Justin Bieber, infuriating throngs of bad-tempered and jealous teenage girls). Barely-teenage pop singer Rebecca Black gets them — as do President Obama, Wisconsin politicians who voted to curb some collective bargaining rights and certain scientists who believe climate change is real.

If you want to know what happens when people get swept up in a mob mentality, look at the Vancouver riots after the Boston Bruins beat the Vancouver Canucks in game seven of the Stanley Cup finals in June. One teen is paying dearly for joining in. Once his image was identified in shots of the action, another mob turned on him. Social media posts have whipped up a frenzy of antipathy toward the youth, who is now in hiding.

An editorial in the Vancouver Sun sums up my feelings when it comes to mob mentality. It was addressing his situation, but applies to others:

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"The court of public opinion should observe common decency as well as the limits of its jurisdiction and leave punishment to the legal system."

The radio program "This American Life" did a program on mob mentality a decade ago that resonates with me. A junior high teacher in 1973 had incited students to a mob mentality in what they did not know was an experiment. A quarter-century later, students the program tracked down remembered vividly the event.

One said she couldn't remember what they were fighting for. But she had never forgotten the feeling of belonging, the power, the fear, the unity.

Or the encounter with her own dark side.

Deseret News staff writer Lois M. Collins may be reached by email at Follow her on Twitter at loisco.