The decision could make existing patents a bit less valuable than before. Whether it will achieve the desired effect of spurring useful innovation or not is an open question.
It will probably take years for the results in the real world to shake out. The idea behind patents is that granting an inventor or innovator the exclusive right to profit or benefit from his or her innovation for a period of years would encourage the progress of science and useful innovation.
Expect plenty of litigation for several years.