Lush is a popular shop over the holidays. They sell body products ranging from soaps to scented body powder.

The marketing is great. Every product comes with an entertaining write up, and slightly saucy name (e.g. Silky Underwear for scented body powder). Lush also has a personal, hand-crafted feel; each batch of product has a sticker that identifies who made the product and when it should be used by.

Lush has a store in downtown San Francisco. Three of us visited the store one day, one of whom is a big Lush fan. She stocked up and her enthusiasm convinced me and the third person to buy some products. (Two more customers for Lush.)

I am not a huge user of beauty products, so my purchases there tend to be minimal. But I know someone who is a big fan of such things. On a subsequent trip, I picked up some body powder for her as a gift and introduced her to Lush.

She loved it. In fact, she loved it so much that she receives Lush products every birthday and Christmas, and makes an effort to visit the store whenever she's in the city. (One more devoted customer for Lush.)

Recently, when stuck for a gift idea, she bought five friends in a writing group Lush products for Christmas. (Five more potential customers for Lush.)

By my count, this one friend has introduced at least three new customers to Lush, and potentially as many as eight (or more) with no extra marketing dollars spent. (I've joked with my friend that she should get a commission on all of this.)

While I'm pretty sure that this chain of events is untrackable by a marketer, it's a concrete, though small, example of how effective word-of-mouth marketing can be for a distinctive high-quality product.

It's also worth noting that if Lush's quality slips, the loss of customers through this same network would occur just as efficiently.