The CIA has certainly taken to enjoy using it's Twitter account. Most recently, the clandestine agency tweeted about their most read documents of 2014 and highlighted one about their U2 program (pdf). Essentially, the CIA took credit for more than half the UFO sightings from the 1950s through the 1960s based on the aircraft's ability to fly so much higher than anybody thought possible back in the day. Their basis for assuming they were the UFOs was made on correlating UFO reports against their log (previously classified) of U2 flight activity. Of course, the CIA's revelation only accounts for half the UFOs, the rest are still unknown.