My daughter developed a rapid and acute love for Ryan's Toy Review (which started as an actual demonstration of toys, but very quickly converted to a heavy and subversive push to sell their own product line). It's been a slow process of steering her away from that content without being too overbearing and triggering a backlash of tears and acrimony, since she's too young to understand the reasoning if we just cut it off and say "no, it's not good for you"