Good article. I'm actually kind of afraid of yoga! Partially because people claiming to be experts can be asking you to do all kinds of things that might be more than you are really able to do, so under the guise of easy, relaxing exercise you can really over do it. But also because they claim head stands are good for you. That is not even possible!
I'm not saying all yoga is bad, I'm just saying all yoga teachers are not created equal.