That's the first I've heard of that site but I can see how it makes money. It's product-crazy. I have no doubt that some people make a lot of money but probably a lot just get by. My teacher also has mentioned how it took her many years to get to the level where she could even begin to teach full-time.

Some teachers might have their own products but usually they are still personally required. It's not unlike programmers selling their time. Many of the teachers do it because they like dancing, not running a business just like some programmers who like programming and don't like the business side. Anyway, it's a fascinating industry to me.