NEW YORK: Just 16% of web users, known as "mass influencers", are responsible for generating the vast majority of online word-of-mouth about brands in the US, a new study has found.

Forrester, the research firm, conducted a survey of 10,000 Americans in order to discover how they used social media to express their opinions about goods and services.

It argued that 16% of the US online population were "mass influencers", a demographic that produced over three-quarters of the user-generated content discussing brands by name in 2009.

More specifically, 6.2% of the internet audience in America - some 176 million people- were defined as being "mass connectors".

This group created 80% of the 256 billion "influence impressions" on social networks last year, taking the form of material such as brand-related comments on Facebook newsfeeds or tweets on Twitter.

A further 13.4% of netizens were said to be "mass mavens", who produced around 80% of the 1.64 billion "influence posts" made on other social media portals like YouTube, blogs and forums in 2009.

Some 7 million people, or 3.7% of the total number of web users, fitted both the mass influencer and mass maven profiles.

Overall, Forrester estimated that social media delivered 500 billion commercial impacts last year, based on a conservative estimate about how many individuals viewed "influence impressions" and "influence posts".

This compared with 2 trillion impressions resulting from formal online advertising, but despite this numerical disparity, peer-to-peer based communications may actually have more influence.

"People make one quarter as many impressions on each other as advertisers make," said Josh Bernoff, svp, idea development, at Forrester.

"These impressions are more credible because they come from people who don't have a bias. They don't come from marketers trying to convince you to buy something."

As such, it is essential that brands attempt to reach the key influencers in their category, with the exact make-up of this group tending to vary depending on the specific sector.

For example, when Forrester used genuine data for a fictitious high-definition television brand, it found that the typical "mass influencer" in the consumer electronics segment was young, male and affluent.

"Mass connectors" in this sector were four times more likely to have a Twitter account and read tweets, and ten times more likely to solicit the views of friends making a big-ticket purchase.

"Mass mavens" in this market also more than doubled the average score when asked if they were always consulted by friends and family looking to buy a consumer electronics product.

One way marketers can leverage this kind of offline influence, Forrester said, would be to hold sponsored "house parties" where brand advocates spread word-of-mouth about their favourite products.

This kind of face-to-face interaction is vital, as while many shoppers become aware of goods and services from mass influencers, they place more trust in their own research, their friends and family.

Turning back to the web, Forrester suggested that the best way to encourage online buzz among the broadest possible audience was to make content "drop dead easy" to spread.

Data sourced from Forrester/Mediapost; additional content by Warc staff