"In the US, you even lose legal rights if you store your data in a company’s machines instead of your own," Stallman told The Guardian. "The police need to present you with a search warrant to get your data from you; but if they are stored in a company's server, the police can get it without showing you anything. They may not even have to give the company a search warrant. I suppose many people will continue moving towards careless computing, because there's a sucker born every minute. The US government may try to encourage people to place their data where the US government can seize it without showing them a search warrant, rather than in their own property. However, as long as enough of us continue keeping our data under our own control, we can still do so. And we had better do so, or the option may disappear."
Stallman is basically saying that he sees Chrome OS as another example of governments pushing for easier access to user data without having to jump through too many legal hoops. Google's argument, meanwhile, is that users will like not having to clean their HDD, perform local backups, and do other maintenance tasks for local files. The search giant is hoping that those benefits will outweigh any potential privacy concerns (that general strategy has largely worked for Google so far). In fact, Mountain View has already declared its belief that 60 percent of businesses could immediately replace their Windows machines with computers running Chrome OS.