Chances are you probably have more Facebook friends than you can keep up with.
In a study by the Royal Society of Open Science, research found that the typical person has about 150 relationships in real-life. The anthropologist who conducted the survey looked at users on Facebook and found they each had about 150 followers but could only count on about four of those friends in a time of crisis.
He says the average person could count just about 13 people as close friends.
The survey also found that social networks encourage "promiscuous friending" -- where you become Facebook friends with someone when there really isn't a strong link.