[
www.nytimes.com]
As far as I can tell, it means that agencies will have to do less overlap collection - if the NSA already has access to some data, the CIA or the FBI doesn't need to waste its time gathering the data again, they can just submit a request to the NSA to obtain it. Will increase efficiency and free up resources for other things. It further means that the NSA can't censor or screen data going towards other intelligence agencies. Its breaking down bureaucratic barriers between intelligence agencies that have been up since the cold war.
On the other hand, there's the general possibility of "big brother" usage of this data - although intelligence agencies right now probably don't have the time, energy, or ability to abuse this data for personal profit or political gain, that doesn't mean it'll be like this forever. The Kremlin is a good example of an intelligence agency that profited immensely from abusing its privileged information for personal gain, and a lot of the most powerful oligarchs in Russia today, including Putin himself, were ex-KGB officers who positioned themselves well after the fall of the Soviet Union.
While I don't think the US is in imminent danger of a Soviet Union-esque collapse, I can't guarantee it will remain perfectly stable forever, and there have been intelligence chiefs and officials who abused their powers heavily in the past (like J. Edgar Hoover and his COINTELPRO program). I believe that as long as we remain careful with congressional/executive oversight and add more whistleblower protections on intelligence agencies we can avoid the worst kinds of abuse. I don't know how Trump will change the equation, we'll have to see what he does.