It was a relatively unusual gaffe for Grillo, who is a skilled communicator and author of one of Italy's most widely read blogs, where he had published an effective analysis of the troubled political situation in the Italian capital.
The two episodes revealed not so much that even media gurus can blunder in their communications, but that Twitter offers a swift reply from the "imbeciles" when they do.
The 140-character messages can also play a healing role.
France's Environment Minister Segolène Royal chose the medium to issue an apology after calling for a boycott of Italy's Nutella chocolate and hazelnut spread, which she said in a television interview contributed to deforestation through its use of palm oil as an ingredient.
Italian authorities responded angrily and Ferrero, the manufacturer, insisted all its palm oil was responsibly sourced.
"A thousand apologies for the polemic on #Nutella. Let's agree to put the emphasis on progress," the minister wrote in a placatory tweet last week.
From reputational damage to international diplomatic repairs, the short messages have shown their power to move public opinion in a country famed for the impulsiveness and volubility of its people.
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