from the majority opinion (written by barrett):

To top it all off, the Government’s interpretation of the statute would attach criminal penalties to a breathtaking amount of commonplace computer activity...If the “exceeds authorized access” clause criminalizes every violation of a computer-use policy, then millions of otherwise law-abiding citizens are criminals. Take the workplace. Employers commonly state that computers and electronic devices can be used only for business purposes. So on the Government’s reading of the statute, an employee who sends a personal e-mail or reads the news using her work computer has violated the CFAA. Or consider the Internet. Many websites, services, and databases—which provide “information” from “protected computer[s],” §1030(a)(2)(C)—authorize a user’s access only upon his agreement to follow specified terms of service. If the “exceeds authorized access” clause encompasses violations of circumstance-based access restrictions on employers’ computers, it is difficult to see why it would not also encompass violations of such restrictions on website providers’ computers. And indeed, numerous amici explain why the Government’s reading of subsection (a)(2) would do just that—criminalize everything from embellishing an online-dating profile to using a pseudonym on Facebook.