The famed British broadcaster Sir David Attenborough, known primarily in this country for his series Life on Earth on PBS, once described mankind as the compulsive communicator. Be it through cave drawings or hieroglyphics, man has consistently shown a need to reach out and talk to another human, in Sir David’s view.

But that human need to talk has its pitfalls, none more so than in the age of Facebook, Twitter and e-mail.

Stumbling into the digital pit isn’t limited to the mighty, like former CIA Director Gen. David Petraeus and Marine Gen. John G. Allen, NATO’s top officer in Afghanistan. The Net just as easily snags the little fish as the big ones. The latest is Cooper City Commissioner John Sims, who posted a racially charged rant on Facebook that spoke derisively about African-Americans, Hispanics and Muslims. After receiving 19 “likes” and six comments supporting it, the post was removed.

But not before it was read by some in Cooper City who found it deeply offensive. Former Cooper City Mayor Debby Eisinger rightly called the race-baiting rant “despicable.”

Why do so many public officials show such bad judgment when it comes to communicating online? Mr. Petraeus resigned after his affair with Paula Broadwell, his biographer, was revealed through e-mails investigated by the FBI. Gen. Allen, in turn, was caught up in this scandal when his voluminous e-mails to Jill Kelley were discovered during the FBI investigation.

Ms. Kelley, a Tampa woman who complained to an FBI agent about Ms. Broadwell’s anonymous e-mail threats, started this whole tawdry story.

Even the FBI agent to whom Ms. Kelley complained, Frederic Humphries II, got egg on his face — he once sent an e-mail photo to Ms. Kelley depicting himself shirtless.

Time and again, we have seen public officials, who should know better, forced to own up to bad behavior or bad judgment after their need to communicate the inappropriate got the upper hand. And given the accessibility and multiplicity of our online communications networks, what is said will almost invariably be revealed to more than those to whom it was intended.

Whether it’s sex, racism or just a stupid lapse in judgment that makes otherwise smart people say or do dumb things on the Internet, in this age of effortless digitized communication there needs to be more self-censorship, especially by public officials — from powerful CIA directors to lowly city commissioners. Just because you can say it online doesn’t mean you should.