Facebook knew this could happen. In a February SEC filing, which includes an obligatory meditation on every conceivable risk to future profits, Facebook warned that “unfavorable publicity regarding, for example, our privacy practices … [or] the actions of our developers whose products are integrated with our products” could imperil “the size, engagement, and loyalty of our user base.” True to form, the $500 billion social networking behemoth’s stock plummeted after news broke Mar.