Web Attack Martin S. Sorrell, CEO of advertising agency WPP Group, sues two blogging ex-colleagues for a Web hate campaign in which, he says, they smeared him and his former lover. The Washington Post grapples with a surge in online comments that read like the racist garbage on neo-Nazi Web sites. Home Depot's (HD ) CEO goes into an emergency huddle with his crisis management team after 14,000 bilious customers storm an MSN (MSFT ) comment room. The venom of crowds isn't new. Ancient Rome was smothered in graffiti. But today the mad scrawls of everyday punters can coalesce into a sprawling, menacing mob, with its own international distribution system, zero barriers to entry, and the ability to ransack brands and reputations. No question, legitimate criticism about companies should get out. The wrinkle now is how often the threats, increasingly posted anonymously, turn savage. Even some A-list bloggers are wondering if the cranks are too often prevailing over cooler heads....