As the mother of a toddler, I think diapers and toilet training when I see the letter "p" followed by a couple of "o"s. But the "poo" in "no poo" isn't Number Two; it's shampoo!
As I recently learned, there's a movement afoot to forgo lathering up your locks with store-bought stuff in favor of using various combinations of things like baking soda, vinegar, and lemon juice. The advantages? You keep the nasty chemicals found in numerous shampoos away from your body and the environment, you use less plastic, and you save money.
I'm already a member of the Church of Not Shampooing Every Day, and I'm considering going "no poo," but I think I'll use up my current bottle first. I'll let you know what happens!
But in the meantime, if you do decide to say adios to your shampoo, don't use Arm & Hammer baking soda—apparently the company conducts some rather regrettable animal testing related to this product. (I have an email in to the company to get confirmation of this, but it seems fairly well established, as far as I can tell.) Bob's Red Mill makes a cruelty-free alternative, though for some reason it doesn't trumpet this fact.