I didn't understand when the news showed up this morning but various sources have conspired to explain it till I do. Essentially, we've found a way to measure a phenomena that was previously invisible to us. Being able to reliably detect and measure makes it go from theory to fact, and gives us a new access to information. Like tracing the point of a pebble dropped in a pond by measuring the ocean's waves, it's not easy but they can in fact figure out where things are, or were, and what they did!
Pretty nifty for future space travel, actually, since these gravitic waves are likely a good way to navigate.
There's a polynesian culture that builds maps of the ocean with bamboo sticks woven into a structure that represents the wave patterns and currents. With this, they can navigate vast distances around the south pacific. Astrophysicists can now use these gravitic waves similarly.