the NSA "wanted the country's largest tech and telecommunications firms to hand over their customer information in bulk, whether by sending it to the NSA themselves or (even better) by allowing the NSA to attach its own secret pipelines to company servers that would extract the information as it came in. Between 2007 and 2012, Microsoft, Yahoo, Google, Facebook, YouTube, and Apple all agreed to participate to some extent. In 2011 alone, a group of phone companies that included Verizon, AT+T, Sprint, T-Mobile, MetroPCS, Cricket, and US Cellular received at least 1.3 million government requests for customer data. With these companies on board, the NSA had access to almost the entire telephone, email, and internet search history of the United States" (Beck 396)
largely "metadata," of course (397) (location of caller, duration of call, numbers on both ends)