No lowest common denominator (Score 1)

Creating a dichotomy where you separate your users into "morons" and "sophisticated" users is your first problem. Users are users. They want to use your Web site. If it's easy enough for the least technologically savvy in your audience it probably empowers your more sophisticated users. But the most usable sites find a happy medium. . .

Nielsen himself has a great article about this topic, Novice vs. Expert Users, on his Web site.