The positive intentional act, I guess, is disseminating the material. Proving intent and various ancillary concepts like knowledge, etc, are the bread and butter of prosecutors, so I don't think the act would be as difficult to enforce as you suggest. Sure, there might be corner cases where you can say "oops I forgot to password protect that Dropbox link" but certainly porn websites that don't do age verification will have a hard time arguing their conduct was not intentional.
>>Noboru+(OP)
Which leads to my next questions: What is pornography material? Do drawings qualify? What about text? What about softcore pornography? What about a non-profit outfit? What is the amount of pornography material I need to have for it to be considered disseminating? Someone uploads a few suggestive fan art drawings to my niche bulletin board and now I am liable for a year in jail?
>>Svip+Q
Also, what what methods of sharing? If a 16 year old shares some porn with some friends and it happens to be on a digital system somewhere, can that kids now go to jail for over a year?