At SAoVQ the same question surfaced:

> A big difficulty is that most of us can't really invite friends without spending an hour explaining the concept of anonymous boards, and how it's unrelated to idiots wearing Guy Fawkes masks.

http://www.secretareaofvipquality.net/saovq/kareha.pl/1213505692/16

As a result someone wrote a text called "A Guide to Anonymous Boards", that we are currently improving on this wiki page: http://tanasinn.info/wiki/A_Guide_to_Anonymous_Boards - right now it's not very good, but once it becomes good enough, I think 4-ch could benefit from this too.