A number of well known personalities have faced trouble lately for running their mouths on Twitter—a nightmare that doesn't look like it will go away for PR professionals.

While the overwhelming majority has been offering sentiments of hope and compassion about the crisis in Japan, a few took to Twitter this past week with an entirely different, and resoundingly negative, approach. The culprits: comedian Gilbert Gottfried, entertainer 50 Cent, and “Family Guy” scriptwriter Alex Sulkin.

In the aftermath, Aflac severed its ties ...