As the Snowden revelations continue to come out the latest involves the NSA's internal 'Google' clone, an inter-agency search engine that allows other departments within the government to access the data NSA has gathered.
This is all warrantless collection of information. It's as if the police or any other government agency can drive by your house and come inside and snoop.
It's really beyond that. Based off the way the Internet functions in our lives, they can actually get into your head and see what you're thinking about.