I thought I'd give a little rundown on my experience (so far) of being poo-free / shamPHree. I have super long, fine and greasy hair, and when I read about it previously on MDA I passed it by as something I just figured I could never do.
I knew I had to do something when I was getting a really flakey scalp, despite having moved on to a tea tree dandruff shampoo. I started by stopping the commercial conditioner and using ACV after my wash. I also got down to washing my hair about 3 times a week. After about 2 months of this, I bit the bullet and ditched the shampoo in favour of bicarb soda.
For the first week my hair was pretty greasy, this is despite me using my Mason Pearson hairbrush religiously. Fortunately, I can braid my hair so the grease is less obvious (I hope).
Since then, my hair has really settled down, I use the bicarb and ACV 1-2 times a week, and sometimes midweek I'll just wash my bangs in the sink before work. Generally i never use a hairdryer, except on my bangs - I allow my hair to dry almost completely before twisting into a bun/braids. I hope to make some herbal infusions for the ACV some time in the future to help my flakey scalp even more. The flakes are still there, but no where near as bad as before.
My BF has also had success with no-poo. He had terrible scalp issues, and keeps it under control by rinsing in the shower about twice a week.
Hope this inspires other folk to try the shamPHree method!