1. Lenhart, A., Madden, M.: Social networking websites and teens: An overview (2007), http://www.pewinternet.org/~/media//Files/Reports/2007/PIP_SNS_Data_Memo_Jan_2007.pdf
2. Ye, S., Lang, J., Wu, F.: Crawling Online Social Graphs. In: The 12th International Asia-Pacific Web Conference (APWEB), pp. 236–242 (2010)
3. Alim, S., AbdulRahman, R., Neagu, D., Ridley, M.: Data retrieval from online social network profiles for social engineering applications. In: International Conference for Internet Technology and Secured Transactions, pp. 1–5. IEEE, Los Alamitos (2009)
4. Top 10 Social Networking Websites & Forums (November 2010), http://www.marketingcharts.com/interactive/top-10-social-networking-websites-forums-november-2010-15359/ (last accessed on 11-01-2011)
5. Caverlee, J., Webb, S.: A large-scale study of MySpace: Observations and implications for online social networks. Artificial Intelligence 8, 36–44 (2008)