Is unnecessary complexity "sticky" or just irritating? Ben Kunz deals with this question in a fascinating post, "Confusion as a design tool" on Thought Gadgets. He notes that despite its constant tinkering and tweaking, Facebook remains extraordinarily popular. Len Kendall suggests that part of the appeal is the complexity - it's like a puzzle or a game where you move to higher levels as your skills improve. Has Facebook stumbled upon a brilliantly counterintuitive marketing strategy -- keep 'em guessing, and keep 'em slightly annoyed ... and they'll keep coming back for more?