From What You Think You Know About the Web Is Wrong by Chartbeat CEO Tony Haile:
The people who share content are a small fraction of the people who visit that content. Among articles we tracked with social activity, there were only one tweet and eight Facebook likes for every 100 visitors. The temptation to infer behaviour from those few people sharing can often lead media sites to jump to conclusions that the data does not support.
A widespread assumption is that the more content is liked or shared, the more engaging it must be, the more willing people are to devote their attention to it. However, the data doesn’t back that up. We looked at 10,000 socially-shared articles and found that there is no relationship whatsoever between the amount a piece of content is shared and the amount of attention an average reader will give that content.