Forrester Research has analysed the peer influence behaviours of online Europeans, based on a survey of 14,000 people in seven Western European countries.
The report, called "Using Social Media To Create Mass Reach – The 2010 European Peer Influence Analysis", found that just 4% of online users in Europe are responsible for triggering 80% of "consumer brand influence impressions".
Forrester also found that only 11% of online adults in Europe create and trigger 80% of all the influence posts online.
Between them, these two types of "European Mass Influencers" will have triggered more than 120 billion "influence impressions" about marketers' products, services, and brands in 2010.
Influence impressions are impressions that have come about as a result of one consumer being influenced by another to click onto online portals for products, services, and brands.
The report names people who create influence impressions as "Mass Connectors". These people have an average 425 friend connections across their social networks and are most likely to share opinions through Facebook.
In contrast, the report says Twitter barely registers as a channel for Mass Connectors and influence impressions.
Nate Elliott, Forrester analyst, said: "Many of the interactive marketers we speak to focus on finding a handful of big (social) names and getting them to talk about the marketer's brand.
"But our Peer Influence Analysis shows that marketers need to go deeper – both in their strategy and in their measurement – to find and leverage a wider range of influential consumers."