Social Network / List / eHow

http://en.wikipedia.org/wiki/Social_network
http://en.wikipedia.org/wiki/List_of_social_networking_websites
http://www.ehow.com/social-networking-sites/
40 Most Popular Social Networking Sites of the World
http://www.socialmediatoday.com/soravjain/195917/40-most-popular-social-networking-sites-world

International firms use social networks to retain talent

http://www.samachar.com/International-firms-use-social-networks-to-retain-talent-lgfvJ9hfjbi.html