A discomfort is sweeping through Europe about the ways in which Internet companies treat personal information. That discomfort has, in turn, prompted proposals for stricter regulation of online data across the continent. And Europe’s moves to protect Internet privacy — something Americans have not, as yet, actively agitated for — have given rise to a thorny question: How do the laws and mores of different nations manage, if at all, the multinational companies that now govern our digital lives?