The relevant part of the act would be: "Intentionally accessing a computer without authorization to obtain ... information from any protected computer". A "protected computer" is a computer "which is used in or affecting interstate or foreign commerce or communication", which fits Craisglist pretty well.
Violation of the clause I quoted is a criminal offense with potential jail time.
That clause could be construed in any number of ways. Anyone accessing a web page could be liable if they have not 'obtained authorization' from the site owner.
