It really depends upon the topic and upon how much inferential difference there is between your ideas and the reader's understanding of the topic. Eliezer's earlier posts are easily understandable to someone with no prior experience in statistics, cognitive science, etc. because he uses a number of examples and metaphors to clearly illustrate his point. In fact, it might be helpful to use his posts as a metric to help answer your question. In general, though, it's probably best to repeat yourself by summarizing your point at both the beginning and end of your essay/post/whatever and by using several examples to illustrate whatever you are talking about, especially if writing for non-experts.