Usenet worked fairly well when you could really only get there by knowing someone. No commercial ISPs, so if you got banned, you really could face penalties at your university (I know because I was a witness at a student trial involving doing things they shouldn't on the Internet - not Usenet specifically - and while it was in no way criminal, the students were sanctioned). And you couldn't just open up a new email account with a new provider and ISP five minutes later.