Social networks are very popular these days, and it facilitates search and retrieval of information through internet. Hence, our understanding and usage of the WWW significantly differs from early days. The Internet, particularly the WWW is not only being used and approached for gathering information anymore. It is used routinely to reach other people through various applications ranging from email, chats, community platforms and social network sites. The current development of the WWW increasingly allows more people to publish information in social networks. Whereas users have changed from passive recipients of information to active content consumers and creators, and the nature of information has also changed from static text to dynamic multimedia. With the widespread use of social networks, live User-Defined Information (UDI) has begun to overcome the Internet. Such UDI covers a range of social network. More research works have focused on analyzing, organizing, indexing, and retrieving information, search for dynamic and live UDI's from the web. However, research efforts to make sense of the huge and unstructured UDI have begun. Social networks and multimedia content sharing Web sites have become increasingly popular in recent years. Information Retrieval is one of the most focused research area which motivate us to concentrate on this field.

1. Flickr Web site. (Online). Available: http://www. flickr. com
2. Picasa Web site. (Online). Available: http://picasa. google. com
3. YouTube Web site. (Online). Available: http://www. youtube. com
4. Facebook Web site. (Online). Available: http://www. facebook. com
5. E. Barnett. (2011, Oct. ). 3. 4 billion photographs on Google+ in 100 days. (Online). Available: http://www. telegraph. co. uk/technology/google/8838196/3. 4-billion-photographs-on-Google-in-100-days. html
6. Google Inc. (2011, Dec. ) YouTube statistics. (Online). Available: http://www. youtube. com/t/press_statistics.
7. A. Sadilek et al. , ''Finding Your Friends and Following them to Where You Are,'' Proc. 5th ACM Int'l Conf. Web Search and Data Mining (WSDM), ACM Press, 2012
8. A. Saha et al. , ''Learning Evolving and Emerging Topics in Social Media: A Dynamic NMF Approach with Temporal Regularization,'' Proc. 5th ACM Int'l Conf. Web Search and Data Mining (WSDM), 2012, pp. 693_702.
9. Z. Ming et al. , ''Prototype Hierarchy Based Clustering for the Categorization and Navigation of Web Collections,'' Proc. 33rd Int'l ACM SIGIR Conf. Research and Development in Information Retrieval, ACM Press, 2010, pp. 2_9.
10. L. Tang et al. , Community Detection and Mining in Social Media, Morgan & Claypool Publishers, 2010.
11. H. Liu et al. , ''Robust Clustering as Ensemble of Affinity Relations,'' Proc. 24th Ann. Conf. Neural Information Processing Systems (NIPS), Curran Associates Publisher, 2010, pp. 1414_1422.
12. S. Liu et al. , ''Street-to-Shop: Cross-Scenario Clothing Retrieval via Parts Alignment and Auxiliary Set,'' Proc. IEEE Computer Soc. Conf. Computer Vision and Pattern Recognition (CVPR), IEEE CS Press, 2012.
13. G. Li et al. , ''Desks: Direction-Aware Spatial Keyword Search,'' Proc. Int'l Conf. Data Eng. (ICDE), IEEE CS Press, 2012, pp. 459_470.
14. L. Shi et al. , ''S3: An Efficient Shared Scan Scheduler on MapReduce Framework,'' Proc. 2011 Int'l Conf. Parallel Processing (ICPP), IEEE CS Press, 2011, pp. 325_334.
15. D. Carmel, N. Zwerdling, I. Guy, S. Ofek-Koifman, N. Har'El, I. Ronen, E. Uziel, S. Yogev, and S. Chernov, "Personalized social search based on the user's social network," in Proc. CIKM, 2009, pp. 1227–1236.
16. Y. Cai and Q. Li, "Personalized search by tag-based user profile and resourceprofile in collaborative tagging systems," in Proc. CIKM, 2010, pp. 969–978.

User Defined Information ( Udi ) Information Retrieval( Ir ) Internet Social Networks Multimedia World Wide Web(www) Traditional Ir And Web Ir Systems