text: Buy, Sell, Insult (Forbes.com) Forbes.com - Patrick Byrne, 42, likes to describe himself as a pugnacious Irish Catholic. He's not kidding. Chief executive of Overstock.com, an online retailer, Byrne has been getting into stunning, knockdown fights with analysts critical of his company. Witness Byrne's scathing e-mail replies to Donn W. Vickrey, cofounder of Camelback Research, a Wall Street research firm in Scottsdale, Ariz. that had published a series of negative reports about Byrne's discount shopping Web site. A sampling from October: