NASA's Monday news release on the dark matter issue did not turn up anything not covered in the 'leaked' press beforehand. (See this previous thread).
The main feature is that a collision between two galactic clusters managed to separate the normal matter from the dark matter. The normal matter is radiating copious amounts of x-rays and the dark matter acts as a gravitational lens for more distant objects. And the two types of matter are no longer in the same spot.
If all of this is confirmed above reasonable doubt, the alternative theories attempting to explain the universe and cosmology are in for a tough time... Read more in Spaceflight Now.