A recent article in Ad Age points out that there is a difference between being popular and driving behavior through influence. Marketers targeting "influentials" need to beware the Twitter and Facebook darlings, as they may not be quite as influential as their numbers may suggest. 

The article cites research from Yahoo! that investigated online chain reactions and found them very difficult to predict. In fact, one looking to create a groundswell through viral Internet activity may be better off targeting average users than singling out one or two "power" users. 

For example, while a celebrity may tweet to millions of followers, how many will re-tweet that? That re-tweet may be more important than the original, because the followers of an ordinary tweeter are more likely to be on a more direct relationship - thus there may be more influence. 

Looking at how many Twitter followers or Facebook friends someone has to decide how influential they are can be a dangerous road to follow when analyzing a marketing or social media strategy. Better to concentrate on a message that resonates with a core group of true believers.