Power of Word-of-Mouth

Two of the most common Internet applications — Google search and AOL instant messager — were essentially built on word-of-mouth advertising.

Google has managed its success despite spending less than 8% of its 2004 revenue on sales and marketing, building the brand almost solely by word of mouth.

Morningstar analyst Rick Summer
An email newsletter I got today pointed out AOL is doing its FIRST national ad campaign for AIM as it launches the AIM Triton product.
Update: Here a story about the branding campaign for AIM.