I thought this was another good example of customer evangelism. Aigner-Clark spent very little money on advertising. What she did was leverage the already established networks of mothers and their play groups. Somebody would mention how much their child enjoyed a video and the word spread.
Mothers in the media also took notice. Baby Einstein ended up with features in People, Time, and Oprah.
There are other good tips on product launches, balancing relationships with customers, and knowing when to sell your business.