• by Gavin O'Malley  @mp_gavin, March 23, 2010

Coinciding with the rise of social networks and viral marketing, "influencers" were once touted as the surest path to broad brand approval. More recently, research has cast doubt on the vastness of their power.

A new study from ICOM -- a division of direct marketing agency Epsilon -- finds that there is no universal influencer, and that consumers are influencers strictly within product categories, rather than across all categories.

In addition, few commonalities exist within demographics for influencers, according to the study. On the contrary, influencers cross gender, age, income levels and channels.

To engage the appropriate influencers, marketers should not target a specific demographic or channel, according to Gillian MacPherson, senior director of product marketing and insight at ICOM. Rather, understanding their behavior is critical.

"While we already know that influencers are a prime audience for today's marketer, it is critical that we also understand their attributes, channel preferences, and behavior," said MacPherson. "Only then will marketers be able to effectively communicate with this valuable segment of the population."

According to MacPherson, the findings are the culmination of three years of research, which was based on two surveys of nearly 7,000 consumers in the U.S. and Canada for the combined sample of influencer households and non-influencer households.

Once targeted based on their behavior, influencers can be engaged with a tailored message across multiple channels, thus becoming a brand ambassador, says MacPherson.

Messages should be familiar and conversational, since influencers talk more frequently person-to-person. While influencers tend to do their talking in person, there is an opportunity to broaden their message through new channels such as social media.

In addition, influencers are highly motivated by being able to give feedback directly to brands and manufacturers. They are are also more likely to sign up for brand Web sites or e-newsletters, as they like to be among the first to hear about new products and information.

One of the first studies to seriously cast doubt on influencers' limitless authority was released by Canadian research firm Pollara in mid-2008. Based on the responses of some 1,100 adults, it found that self-described social media users put far more trust in friends and family online than in popular bloggers, or strangers with 10,000 social network "friends."

Nearly 80% said they were very or somewhat more likely to consider buying products recommended by real-world friends and family, while only 23% reported being very or somewhat likely to consider a product pushed by "well-known bloggers."