The barbs on both sides of the Atlantic could backfire. Even as they help draw attention to Google practices that may prod some consumers to try different services, they also serve as a reminder of Microsoft's mostly futile - and costly - attempts to trump its rival with more compelling technology. "It's always the underdog that does negative advertising like this, and there is no doubt that Microsoft is now the underdog," said Jonathan Weber, who has been following Microsoft's "Scroogled" campaign at search consulting firm LunaMetrics. On the flip side, Google has evolved from an endearing Internet startup to an imposing giant running Web and mobile services that vacuum intimate details about people's lives. Despite repeated management assurances about respecting personal privacy, Google has experienced several lapses that have resulted in regulatory fines, settlements and scorn around the world. Beyond privacy, Google has been portrayed as an abusive bully in various complaints about its business practices.