I'd like to point out a specific dutch criminal case from 2010 regarding 4chan, since the judge's decision and reasoning might interest the community. I'll translate it from the official juristicial site of the netherlands: https://uitspraken.rechtspraak.nl/inziendocument?id=ECLI:NL:RBSGR:2010:BM1481
TLDR: anon posts he's gonna shoot up the school on /b/, judge determines /b/ is full of shitposts and there's a disclaimer, anon goes free.
Not guilty. Suspect has posted on the website www.4chan.org that he would kill several people of the Maerlant College. He has used his neighbour's router and/or encrypted wireless connection to do so. The words used in the post by the suspect can, as determined by the judge, be cause of criminal threat to the lives of students and teachers of the Mearlant College. For a punishable threat, however, it is required the suspect has had a (conditional) intent to do so. The court has judged that with the specific circumstances under which this message is placed it can not be determined that the suspect has wittingly accepted the significant chance that fear of life could originate among students and/or teachers of the Maerlant College. Reason for this being primarily the context of the 4chan-website, including the warning placed thereupon. The testimonies of the suspect about the character of the website and the concerning forum upon which such messages can be placed as a sort of game support that. The court determines the suspect not guilty of the accusation in section 2.
The disclaimer, quoted literally in the court proceedings: "The stories and information posted here are artistic works of fiction and falsehood. Only a fool would take anything posted here as a fact"
Why is this interesting, you ask? This site is already home to calls to gas the jews and to decorate trees. People on this site are expected to understand the nuances of gassing jews, but how are you going to explain them to a judge? How do you back up your claims? On 4/pol/ I've seen one or more people posting with a name à la "All posts by this IP are ironic/satirical", which really shouldn't be necessary, since 4/pol/ users are implicitly expected to understand about shitposting and layered irony.