Here's the key language:
[T]he question is whether individuals of "common intelligence" are on notice that a breach of a terms of service contract can become a crime . . . . Arguably, they are not.
And, as any good student of fair notice jurisprudence knows, if it's arguable that a course of conduct isn't within the scope of a criminal statute, the constitution says the conduct isn't subject to prosecution.
Thus, the court concludes that,
Treating a violation of a website's terms of service, without more, to be sufficient to constitute "intentionally access[ing] a computer without authorization or exceed[ing] authorized access" would result in transforming section 1030(a)(2)(C)
into an overwhelmingly overbroad enactment that would convert a multitude of otherwise innocent Internet users into misdemeanant criminals.
The opinion is thorough in its analysis and makes a number of great points. My hope is that this is a high water mark in federal government over prosecuting, but my fear is that this case will be cited a lot. If you've read this far, you should probably check it out.
If you have questions about how federal criminal charges are different than state criminal charges, please visit this page on Maryland federal criminal charges or Washington DC federal criminal charges.