College students, like many young people, are strongly influenced by word of mouth and look to their friends for advice. With the rise of social networking, blogs and viral video, this group has many new user-generated sources for information about products and services.

According to Youth Trends, word of mouth is the top way students like to learn about new products and services. TV advertising ranked second, although it was a more powerful driver for females than males.

"The fact that students favor word of mouth, combined with their use of social networking, indicates that they are a strong audience for online word-of-mouth marketing efforts," said eMarketer senior analyst Debra Aho Williamson.

Word of mouth also figured strongly in the results of William Blair's "Millennials Survey" with 85% of college students saying they primarily learned about new products this way. The next most frequently cited source was in-store marketing, with close to 70% choosing this method. William Blair conducted the study between September and November of 2006.

Both Facebook and MySpace are moving in the direction of online word of mouth. Facebook founder Mark Zuckerberg told Time magazine that "people are trying to communicate in a certain way on Facebook—they share information with their friends, they learn about what their friends are doing—so there's really a whole new opportunity for a new type of advertising model within that."

In a Ketchum-Annenberg Center study of the types of media US adults had used to gain information in the past month, word of mouth was far more common among young adults. Half of those age 18 to 24 and 24 to 34 had received advice from family or friends, compared with 39% of those 55 to 64 and 29.6% of those 65 and older, according to the study.

In fact, young people 18 to 24 were nearly as likely to get information from friends and family as they were to get it from local newspapers or local TV news. Among people 35 to 44, by comparison, newspapers and TV news were much more likely than word of mouth to be used for information.