That's interesting-- Curly Girl claimed that shampoo was unnecessary, but a brief experiment seemed to imply that not using shampoo left my hair feeling nasty. It's possible I didn't run the experiment long enough.

This is consistent with what I've heard and personally experienced. I gave up shampoo about 1.5 years ago, but then some time later switched, at the recommendation of my mum who has very similar hair to mine, to a product that's actually called No Poo. It does some sort of cleansing thing but doesn't actually lather/foam like soap. I use it once every 1-2 weeks and my hair is absolutely wonderful. It's nearly a foot long when straight, fwiw.