An interesting survey done by one of the main online job bank sites. The sample is the job seekers/users of the site. But, it is still an interesting finding.
52% of the 2,732 people surveyed in this study indicated that they are Facebook users.
Of these Facebook users, 60.5 % said they use it for networking, but only 18% of their Facebook friends are their co-workers.
Of these Facebook users, 50.7 % said they use it to play games and 17.6 percent said they use it to look for classmates with whom they have lost contact.
In a sense, I think, people don’t necessarily consider coworkers as close friends or friends that they would hang out beyond the work setting. For most people, only a handful of their coworkers would be considered as close friends. In order for coworkers to be friends, they would have to talk about things other than work. You need a bit more tie strength/closeness to pass that threshold of being merely a coworker.
So, in my opinion, the usage pattern of these Taiwanese Facebook users suggested that they use Facebook to connect with their stronger ties, not their weaker ties.
http://www.chinapost.com.tw/life/2010/11/14/279813/52-percent.htm