The detection of a black hole merger through gravitational waves signaled the opening up of new ground in astronomy. Until that moment, astronomers had only one way to observe the Universe: via the electromagnetic spectrum. It is hoped that gravitational waves will let us see further back in time and deeper into general relativity than ever before.
The first generation of gravitational wave detectors, which are able to detect spatial movement on the order of 10-21m, are the finest and most sensitive listening devices ever made. And now they are listening for black hole mergers.
Unfortunately, in practice, the current generation of gravitational wave detectors is a bit like your granddad. No, they are not deaf, but you still need to shout to get their attention. Or, to put it more directly, only the most energetic and closest events are going to get the attention of advanced LIGO and advanced VIRGO. As a result, researchers are asking themselves if clever signal processing can be used to extract more information from the instruments that are coming online now.