In a letter last week to Rep. Jim Sensenbrenner, the U.S. Department of Justice said intelligence tools that NSA uses to identify the existence of potential terrorist communications within the data "require collecting and storing large volumes of the metadata to enable later analysis." If the data is not collected and held by the NSA, the metadata may not continue to be available for the period that it "has deemed necessary for national security purposes" as it need not be retained by telecommunications service providers.
Internet companies like Google, Microsoft and Yahoo have been demanding for greater transparency in the orders of the FISC, after Edward Snowden, the former NSA contractor behind the leak of the Verizon order, also disclosed documents that suggested that the NSA has access in real-time to content on their servers. The companies have denied the claims, and want FISC to remove restrictions that prevent them from disclosing requests for customer data under FISA. Yahoo appears to have persuaded FISC to release its secret order and parties' briefs in a 2008 case. The court ordered the government recently to declassify the documents, as it prepares to publish the court's opinion in a redacted form.