Mark Perry of Carpe Diem on the book price wars:
It's only in the bizarre world of antitrust that any price you charge can be considered illegal. If your price is lower than your competitors, you could be charged with being a "predator" for anti-competitive "predatory pricing." If your price is "too high" you could be charged with anti-competitive monopoly pricing, "price gouging," or "ticket scalping." And if your price is the same as your competitors, you could be charged with collusion and anti-competitive price-fixing.