Forewarned is forearmed: those who feel that employers might take notice of an anonymous snipe are well advised to get in first. Let your employer know that there has been unusual behavior by one or two people in online forums John,
I don't agree with this approach at all. This is far more likely to raise a red (or pink) flag with someone's employer. Rule #1 in employer/employee relations - don't raise suspicions.
There's only one way to deal with this, and it's to punish perpetrators. There's no "secret power" at work here, just individuals who decide to hide behind a private email account and choose to cause trouble.