Most Facebook users receive more from their Facebook friends than they give, according to a new study that for the first time combines server logs of Facebook activity with survey data to explore the structure of Facebook friendship networks and measures of social well-being.

It turns out there are segments of Facebook power users who contribute much more content than the typical user. Most Facebook users are moderately active over a one-month time period, so highly active power users skew the average. These power users constitute about 20%-30% of Facebook users, but the striking thing is that there are different power users depending on the activity in question. One group of power users dominates friending activity. Another dominates ‘liking’ activity. And yet another dominates photo tagging.