Frankly, I'm not certain how much this changes things. I believe that corporations have always been free to contribute to PACs and other avocacy groups to run election ads.
Recenlty, the U.S. Chamber of Commerce has taken on the role of being basically a laundering service for corporate speech. Corporation X pays the Chamber to run an ad against candidate X and the ad says that the U.S. Chamber of Commerce paid for the content of the ad, leaving Corporation X behind the scenes. The court's ruling upheld disclosure requirements on corporate ad buys such that many corporations will still use the Chamber of Commerce model to avoid the disclosure requirements.