The rule changes open up the NSA's trove of raw data to other intelligence agencies, making it easier for authorities to notice trends or spot troublesome communications. However, activist groups including the American Civil Liberties Union argue that relaxing the rules around sharing raw data threatens the privacy of innocent US citizens, according to The New York Times.

These changes have been a long time coming.

The NSA has a sweeping surveillance system that collects satellite transmissions, phone calls and emails that pass through networks abroad, and other bulk communications data. The program is largely unregulated by wiretapping statutes, instead adhering to regulations laid down in the aftermath of the World Trade Center terrorist attacks on September 11th, 2001.

In 2002, the Foreign Intelligence Surveillance Act secretly permitted the NSA and other agencies to share raw, domestically gathered intelligence. In 2008, the FISA Amendments Act legalized warrantless, domestic surveillance when the target was a foreigner abroad, and the Foreign Intelligence Surveillance Court also approved the sharing of raw email data uncovered in these programs.

That same year, President George W. Bush modified Executive Order 12333 -- which regulates surveillance systems not covered in wiretapping laws -- to allow the NSA to share raw surveillance data. However, first the director of national intelligence, the attorney general and the defense secretary had to agree on procedures.

This brings us to 2016.

Attorney General Loretta Lynch signed the new rules on January 3rd, after Director of National Intelligence James Clapper approved them in December. President Barack Obama's administration passed the changes in its final days in the White House -- President-elect Donald Trump takes office on January 20th.

The FBI and other agencies use the systems laid out by the FISA Amendments Act and Executive Order 12333 in different ways, as noted by The New York Times. The warrantless surveillance program enabled by FISA allows FBI agents to search that program's database when investigating ordinary criminal cases. Meanwhile, the 12333 database is limited to agents and national security analysts working only on foreign intelligence or counterintelligence operations. Either way, if an agent sees evidence of an American committing a crime, that information is forwarded to the Department of Justice.

Surveillance isn't the only sector where the US government is attempting to keep up in an increasingly connected world. For example, in December the Department of Justice received expanded powers to search multiple computers, phones and other devices on a single warrant.