S. Amer-yahia, J. Huang, and C. Yu, Building community-centric information exploration applications on social content sites, Proceedings of the 35th SIGMOD international conference on Management of data, SIGMOD '09, pp.947-952, 2009.
DOI : 10.1145/1559845.1559953

S. Amer-yahia, L. V. Lakshmanan, and C. Yu, Socialscope: enabling information discovery on social content sites, 2009.

S. E. Robertson and K. S. Jones, Document Retrieval Systems, Ch. Relevance weighting of search terms, pp.143-160, 1988.

S. Brin and L. Page, The anatomy of a large-scale hypertextual Web search engine, Computer Networks and ISDN Systems, vol.30, issue.1-7, pp.1-7, 1998.
DOI : 10.1016/S0169-7552(98)00110-X

J. M. Kleinberg, Authoritative sources in a hyperlinked environment, Journal of the ACM, vol.46, issue.5, pp.604-632, 1999.
DOI : 10.1145/324133.324140

G. Salton, Automatic Information Organization and Retrieval, 1968.

A. Maaradji, H. Hacid, R. Skraba, and A. Vakali, Social Web Mashups Full Completion via Frequent Sequence Mining, 2011 IEEE World Congress on Services, pp.9-16, 2011.
DOI : 10.1109/SERVICES.2011.98
URL : https://hal.archives-ouvertes.fr/hal-00632947

W. Stanley and F. Katherine, Social Network Analysis: Methods and Applications (Structural Analysis in the Social Sciences), 1994.

T. Hammond, T. Hannay, B. Lund, and J. Scott, Social bookmarking tools: a general review, D-Lib Mag, 2005.

B. Lund, T. Hammond, T. Hannay, and M. Flack, Social Bookmarking Tools (II), D-Lib Magazine, vol.11, issue.04, 2005.
DOI : 10.1045/april2005-lund

D. Goh and S. Foo, Social Information Retrieval Systems: Emerging Technologies and Applications for Searching the Web Effectively, Information Science Reference?Imprint of, 2007.
DOI : 10.4018/978-1-59904-543-6

P. Heymann, G. Koutrika, and H. Garcia-molina, Can social bookmarking improve web search?, Proceedings of the international conference on Web search and web data mining , WSDM '08, pp.195-206, 2008.
DOI : 10.1145/1341531.1341558
URL : http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.210.2819

M. R. Morris, J. Teevan, and K. Panovich, What do people ask their social networks, and why? A survey study of status message Q&A behavior, Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, CHI '10, pp.1739-1748, 2010.

H. Ma, H. Yang, M. R. Lyu, and I. King, SoRec, Proceeding of the 17th ACM conference on Information and knowledge mining, CIKM '08, pp.931-940, 2008.
DOI : 10.1145/1458082.1458205

G. Kumaran and V. R. Carvalho, Reducing long queries using query quality predictors, Proceedings of the 32nd international ACM SIGIR conference on Research and development in information retrieval, SIGIR '09, pp.564-571, 2009.
DOI : 10.1145/1571941.1572038

N. Efthimis and . Efthimiadis, Interactive query expansion: A user-based evaluation in a relevance feedback environment, Journal of the American Society for Information Science, vol.17, issue.11, pp.989-1003, 2000.
DOI : 10.1002/1097-4571(2000)9999:9999<::AID-ASI1002>3.0.CO;2-B

C. Lioma, R. Blanco, and M. Moens, A Logical Inference Approach to Query Expansion with Social Tags, 2009.
DOI : 10.1002/asi.10214

S. Jin, H. Lin, and S. Su, Query expansion based on folksonomy tag cooccurrence analysis, IEEE International Conference on Granular Computing, 2009.

A. Mantrach, J. Renders, R. Baeza-yates, A. De-vries, H. Zaragoza et al., A General Framework for People Retrieval in Social Media with Multiple Roles, Advances in Information Retrieval, pp.512-516, 2012.
DOI : 10.1007/978-3-642-28997-2_53

Y. Lin, H. Lin, S. Jin, and Z. Ye, Social annotation in query expansion, Proceedings of the 34th international ACM SIGIR conference on Research and development in Information, SIGIR '11, pp.405-414, 2011.
DOI : 10.1145/2009916.2009972

M. Bender, T. Crecelius, M. Kacimi, S. Michel, T. Neumann et al., Exploiting social relations for query expansion and result ranking, 2008 IEEE 24th International Conference on Data Engineering Workshop, 2008.
DOI : 10.1109/ICDEW.2008.4498369

R. Schenkel, T. Crecelius, M. Kacimi, S. Michel, T. Neumann et al., Efficient top-k querying over social-tagging networks, Proceedings of the 31st annual international ACM SIGIR conference on Research and development in information retrieval, SIGIR '08, pp.523-530, 2008.
DOI : 10.1145/1390334.1390424

]. C. Biancalana, F. Gasparetti, A. Micarelli, and G. Sansonetti, Social semantic query expansion, ACM Transactions on Intelligent Systems and Technology, vol.4, issue.4, pp.1-6043, 2013.
DOI : 10.1145/2508037.2508041

M. R. Bouadjenek, H. Hacid, M. Bouzeghoub, and J. Daigremont, Personalized social query expansion using social bookmarking systems, Proceedings of the 34th international ACM SIGIR conference on Research and development in Information, SIGIR '11, pp.1113-1114, 2011.
DOI : 10.1145/2009916.2010075

A. Hotho, R. Jäschke, C. Schmitz, and G. Stumme, Information Retrieval in Folksonomies: Search and Ranking, The Semantic Web: Research and Applications, 2006.
DOI : 10.1007/11762256_31

S. Bao, G. Xue, X. Wu, Y. Yu, B. Fei et al., Optimizing web search using social annotations, Proceedings of the 16th international conference on World Wide Web , WWW '07, pp.501-510, 2007.
DOI : 10.1145/1242572.1242640

T. Takahashi and H. Kitagawa, S-BITS : Social-Bookmarking Induced Topic Search, 2008 The Ninth International Conference on Web-Age Information Management, pp.25-30, 2008.
DOI : 10.1109/WAIM.2008.94

T. Takahashi and H. Kitagawa, A Ranking Method for Web Search Using Social Bookmarks, Proceedings of the 14th International Conference on Database Systems for Advanced Applications, DASFAA '09, pp.585-589, 2009.
DOI : 10.1007/11930334_5

Y. Yanbe, A. Jatowt, S. Nakamura, and K. Tanaka, Towards Improving Web Search by Utilizing Social Bookmarks, Proceedings of the 7th International Conference on Web Engineering, ICWE'07, pp.343-357, 2007.
DOI : 10.1007/978-3-540-73597-7_28

F. Abel, N. Henze, and D. Krause, Ranking in folksonomy systems, Proceeding of the 17th ACM conference on Information and knowledge mining, CIKM '08, pp.1429-1430, 2008.
DOI : 10.1145/1458082.1458316

A. Dong, R. Zhang, P. Kolari, J. Bai, F. Diaz et al., Time is of the essence, Proceedings of the 19th international conference on World wide web, WWW '10, pp.331-340, 2010.
DOI : 10.1145/1772690.1772725

X. He, M. Gao, M. Kan, Y. Liu, and K. Sugiyama, Predicting the popularity of web 2.0 items based on user comments, Proceedings of the 37th international ACM SIGIR conference on Research & development in information retrieval, SIGIR '14, pp.233-242, 2014.
DOI : 10.1145/2600428.2609558

M. R. Bouadjenek, H. Hacid, and M. Bouzeghoub, Sopra, Proceedings of the 36th international ACM SIGIR conference on Research and development in information retrieval, SIGIR '13, pp.861-864, 2013.
DOI : 10.1145/2484028.2484131

D. Carmel, N. Zwerdling, I. Guy, S. Ofek-koifman, N. Har-'el et al., Personalized social search based on the user's social network, Proceeding of the 18th ACM conference on Information and knowledge management, CIKM '09, pp.1227-1236, 2009.
DOI : 10.1145/1645953.1646109

M. G. Noll and C. , Web Search Personalization Via Social Bookmarking and Tagging, ISWC'07/ASWC'07, 2007.
DOI : 10.1007/978-3-540-76298-0_27

D. Vallet, I. Cantador, and J. M. Jose, Personalizing Web Search with Folksonomy-Based User and Document Profiles, Proceedings of the 32nd European Conference on Advances in Information Retrieval, pp.420-431, 2010.
DOI : 10.1007/978-3-642-12275-0_37

Q. Wang and H. Jin, Exploring online social activities for adaptive search personalization, Proceedings of the 19th ACM international conference on Information and knowledge management, CIKM '10, pp.999-1008, 2010.
DOI : 10.1145/1871437.1871564

S. Xu, S. Bao, B. Fei, Z. Su, and Y. Yu, Exploring folksonomy for personalized search, Proceedings of the 31st annual international ACM SIGIR conference on Research and development in information retrieval, SIGIR '08, pp.155-162, 2008.
DOI : 10.1145/1390334.1390363

M. R. Bouadjenek, A. Bennamane, H. Hacid, and M. Bouzeghoub, Evaluation of Personalized Social Ranking Functions of Information Retrieval, Web Engineering, pp.283-290, 2013.
DOI : 10.1007/978-3-642-39200-9_24

M. R. Bouadjenek, H. Hacid, M. Bouzeghoub, and A. Vakali, Using social annotations to enhance document representation for personalized search, Proceedings of the 36th international ACM SIGIR conference on Research and development in information retrieval, SIGIR '13, pp.1049-1052, 2013.
DOI : 10.1145/2484028.2484130

X. Zhang, L. Yang, X. Wu, H. Guo, Z. Guo et al., sDoc, Proceeding of the 18th ACM conference on Information and knowledge management, CIKM '09, pp.395-404, 2009.
DOI : 10.1145/1645953.1646005

D. Carmel, H. Roitman, and E. Yom-tov, Social bookmark weighting for search and recommendation, The VLDB Journal, vol.1, issue.1, pp.761-775, 2010.
DOI : 10.1007/s00778-010-0211-9

P. A. Dmitriev, N. Eiron, M. Fontoura, and E. Shekita, Using annotations in enterprise search, Proceedings of the 15th international conference on World Wide Web , WWW '06, pp.811-817, 2006.
DOI : 10.1145/1135777.1135900

K. Bischoff, C. S. Firan, W. Nejdl, and R. Paiu, Can all tags be used for search?, Proceeding of the 17th ACM conference on Information and knowledge mining, CIKM '08, pp.193-202, 2008.
DOI : 10.1145/1458082.1458112

A. Singhal and F. Pereira, Document expansion for speech retrieval, Proceedings of the 22nd annual international ACM SIGIR conference on Research and development in information retrieval , SIGIR '99, pp.34-41, 1999.
DOI : 10.1145/312624.312645

D. Carmel, H. Roitman, and E. Yom-tov, Who tags the tags? A framework for bookmark weighting, Proceedings of the 18th ACM Conference on Information and Knowledge Management, CIKM '09, pp.1577-1580, 2009.

G. Salton, A. Wong, and C. S. Yang, A vector space model for automatic indexing, Communications of the ACM, vol.18, issue.11, pp.613-620, 1975.
DOI : 10.1145/361219.361220

S. Amer-yahia, M. Benedikt, L. V. Lakshmanan, and J. Stoyanovich, Efficient network aware search in collaborative tagging sites, Proc. VLDB Endow, pp.710-721, 2008.

M. Sihem-amer-yahia, . Benedikt, V. S. Laks, J. Lakshmanan, and . Stoyanovich, Efficient network aware search in collaborative tagging sites, Proceedings of the VLDB Endowment, vol.1, issue.1, pp.710-721, 2008.
DOI : 10.14778/1453856.1453934

J. Teevan, D. Ramage, and M. R. Morris, #TwitterSearch, Proceedings of the fourth ACM international conference on Web search and data mining, WSDM '11, pp.35-44, 2011.
DOI : 10.1145/1935826.1935842

D. Horowitz and S. D. Kamvar, The anatomy of a large-scale social search engine, Proceedings of the 19th international conference on World wide web, WWW '10, pp.431-440, 2010.
DOI : 10.1145/1772690.1772735

A. Broder, A taxonomy of web search, ACM SIGIR Forum, vol.36, issue.2, pp.3-10, 2002.
DOI : 10.1145/792550.792552

P. Anick and R. G. Kantamneni, A longitudinal study of real-time search assistance adoption, Proceedings of the 31st annual international ACM SIGIR conference on Research and development in information retrieval, SIGIR '08, pp.701-702, 2008.
DOI : 10.1145/1390334.1390459

R. W. White and G. Marchionini, Examining the effectiveness of real-time query expansion, Information Processing & Management, vol.43, issue.3, pp.685-704, 2007.
DOI : 10.1016/j.ipm.2006.06.005

G. Dror, Y. Koren, Y. Maarek, and I. , Szpektor, I want to answer; who has a question? Yahoo! answers recommender system, Proceedings of the 17th ACM SIGKDD International Conference on Knowledge Discovery and Data Mining, pp.1109-1117, 2011.

J. Zhang, M. S. Ackerman, L. Adamic, and K. K. Nam, QuME, Proceedings of the 20th annual ACM symposium on User interface software and technology , UIST '07, pp.111-114, 2007.
DOI : 10.1145/1294211.1294230

G. Hsieh and S. Counts, mimir, Proceedings of the 27th international conference on Human factors in computing systems, CHI 09, pp.769-778, 2009.
DOI : 10.1145/1518701.1518820

D. H. Dalip, M. A. Gonçalves, M. Cristo, and P. Calado, Exploiting user feedback to learn to rank answers in q&a forums, Proceedings of the 36th international ACM SIGIR conference on Research and development in information retrieval, SIGIR '13, pp.543-552, 2013.
DOI : 10.1145/2484028.2484072

B. J. Jansen, A. Chowdury, and G. Cook, The ubiquitous and increasingly significant status message, interactions, vol.17, issue.3, pp.15-17, 2010.
DOI : 10.1145/1744161.1744165

B. J. Jansen, Z. Liu, C. Weaver, G. Campbell, and M. Gregg, Real time search on the web: Queries, topics, and economic value, Information Processing & Management, vol.47, issue.4, pp.491-506, 2011.
DOI : 10.1016/j.ipm.2011.01.007

T. Peggs, The inner workings of a real time search engine: Thoughts on realtime search, 2009.

M. Efron, J. Lin, J. He, and A. De-vries, Temporal feedback for tweet search with non-parametric density estimation, Proceedings of the 37th international ACM SIGIR conference on Research & development in information retrieval, SIGIR '14, pp.33-42, 2014.
DOI : 10.1145/2600428.2609575

J. Vosecky, K. W. Leung, and W. Ng, Collaborative personalized Twitter search with topic-language models, Proceedings of the 37th international ACM SIGIR conference on Research & development in information retrieval, SIGIR '14, pp.53-62, 2014.
DOI : 10.1145/2600428.2609584

M. R. Morris, Collaborating alone and together: investigating persistent and multi-user web search activities, 2007.

M. R. Morris, A survey of collaborative web search practices, Proceeding of the twenty-sixth annual CHI conference on Human factors in computing systems , CHI '08, pp.1657-1660, 2008.
DOI : 10.1145/1357054.1357312

M. R. Morris and E. Horvitz, SearchTogether, Proceedings of the 20th annual ACM symposium on User interface software and technology , UIST '07, pp.3-12, 2007.
DOI : 10.1145/1294211.1294215

F. F. Filho, G. M. Olson, and P. L. De-geus, Kolline, Proceedings of the 28th ACM International Conference on Design of Communication, SIGDOC '10, pp.89-94, 2010.
DOI : 10.1145/1878450.1878465

S. A. Paul and M. R. Morris, CoSense, Proceedings of the 27th international conference on Human factors in computing systems, CHI 09, pp.1771-1780, 2009.
DOI : 10.1145/1518701.1518974

H. Ma, An experimental study on implicit social recommendation, Proceedings of the 36th international ACM SIGIR conference on Research and development in information retrieval, SIGIR '13, pp.73-82
DOI : 10.1145/2484028.2484059

L. Chen, P. Wei, and W. Zhe, Hete-cf: Social-based collaborative filtering recommendation using heterogeneous relations, The IEEE International Conference on Data Mining, ICDM'14, 2014.

J. Lin, K. Sugiyama, M. Kan, and T. Chua, Addressing cold-start in app recommendation, Proceedings of the 36th international ACM SIGIR conference on Research and development in information retrieval, SIGIR '13, pp.283-292, 2013.
DOI : 10.1145/2484028.2484035

S. Sedhain, S. Sanner, D. Braziunas, L. Xie, and J. Christensen, Social collaborative filtering for cold-start recommendations, Proceedings of the 8th ACM Conference on Recommender systems, RecSys '14, pp.345-348, 2014.
DOI : 10.1145/2645710.2645772

S. Sedhain, S. Sanner, L. Xie, R. Kidd, K. Tran et al., Social affinity filtering, Proceedings of the first ACM conference on Online social networks, COSN '13, pp.51-62, 2013.
DOI : 10.1145/2512938.2512947

F. Liu and H. J. Lee, Use of social network information to enhance collaborative filtering performance, Expert Systems with Applications, vol.37, issue.7, pp.4772-4778, 2010.
DOI : 10.1016/j.eswa.2009.12.061

I. Guy, N. Zwerdling, D. Carmel, I. Ronen, E. Uziel et al., Personalized recommendation of social software items based on social relations, Proceedings of the third ACM conference on Recommender systems, RecSys '09, pp.53-60, 2009.
DOI : 10.1145/1639714.1639725

I. Guy, N. Zwerdling, I. Ronen, D. Carmel, and E. , Social media recommendation based on people and tags, Proceeding of the 33rd international ACM SIGIR conference on Research and development in information retrieval, SIGIR '10, pp.194-201, 2010.
DOI : 10.1145/1835449.1835484

H. Ma, I. King, and M. R. Lyu, Learning to recommend with social trust ensemble, Proceedings of the 32nd international ACM SIGIR conference on Research and development in information retrieval, SIGIR '09, pp.203-210, 2009.
DOI : 10.1145/1571941.1571978

M. Jamali and M. Ester, A matrix factorization technique with trust propagation for recommendation in social networks, Proceedings of the fourth ACM conference on Recommender systems, RecSys '10, pp.135-142, 2010.
DOI : 10.1145/1864708.1864736

X. Yang, H. Steck, and Y. Liu, Circle-based recommendation in online social networks, Proceedings of the 18th ACM SIGKDD international conference on Knowledge discovery and data mining, KDD '12, pp.1267-1275
DOI : 10.1145/2339530.2339728

H. Ma, D. Zhou, C. Liu, M. R. Lyu, and I. King, Recommender systems with social regularization, Proceedings of the fourth ACM international conference on Web search and data mining, WSDM '11, pp.287-296, 2011.
DOI : 10.1145/1935826.1935877

J. Noel, S. Sanner, K. Tran, P. Christen, L. Xie et al., New objective functions for social collaborative filtering, Proceedings of the 21st international conference on World Wide Web, WWW '12, pp.859-868
DOI : 10.1145/2187836.2187952

L. Yu, R. Pan, and Z. Li, Adaptive social similarities for recommender systems, Proceedings of the fifth ACM conference on Recommender systems, RecSys '11, pp.257-260, 2011.
DOI : 10.1145/2043932.2043978

X. Yang, Y. Guo, Y. Liu, and H. Steck, A survey of collaborative filtering based social recommender systems, Computer Communications, vol.41, issue.0, pp.41-42, 2014.
DOI : 10.1016/j.comcom.2013.06.009

J. Chen, W. Geyer, C. Dugan, M. Muller, and I. Guy, Make new friends, but keep the old, Proceedings of the 27th international conference on Human factors in computing systems, CHI 09, pp.201-210, 2009.
DOI : 10.1145/1518701.1518735

G. Groh and C. Ehmig, Recommendations in taste related domains, Proceedings of the 2007 international ACM conference on Conference on supporting group work , GROUP '07, pp.127-136, 2007.
DOI : 10.1145/1316624.1316643

P. Symeonidis, A. Nanopoulos, and Y. Manolopoulos, A Unified Framework for Providing Recommendations in Social Tagging Systems Based on Ternary Semantic Analysis, Knowledge and Data Engineering, pp.179-192, 2010.
DOI : 10.1109/TKDE.2009.85

J. Hannon, M. Bennett, and B. Smyth, Recommending twitter users to follow using content and collaborative filtering approaches, Proceedings of the fourth ACM conference on Recommender systems, RecSys '10, pp.199-206, 2010.
DOI : 10.1145/1864708.1864746

J. Hannon, K. Mccarthy, and B. Smyth, Finding Useful Users on Twitter: Twittomender the Followee Recommender, Proceedings of the 33rd European Conference on Advances in Information Retrieval, pp.784-787, 2011.
DOI : 10.1007/978-3-540-72079-9_10

X. Wang, H. Liu, and W. Fan, Connecting users with similar interests via tag network inference, Proceedings of the 20th ACM international conference on Information and knowledge management, CIKM '11, pp.1019-1024, 2011.
DOI : 10.1145/2063576.2063723

R. Jäschke, L. Marinho, A. Hotho, L. Schmidt-thieme, and G. Stumme, Tag recommendations in social bookmarking systems, AI Commun, vol.21, pp.231-247, 2008.

G. Mishne, AutoTag, Proceedings of the 15th international conference on World Wide Web , WWW '06, pp.953-954, 2006.
DOI : 10.1145/1135777.1135961

A. Hotho, R. Jäschke, C. Schmitz, and G. Stumme, Folkrank: a ranking algorithm for folksonomies, p.LWA, 2006.

R. Krestel, P. Fankhauser, and W. , Latent dirichlet allocation for tag recommendation, Proceedings of the third ACM conference on Recommender systems, RecSys '09, pp.61-68, 2009.
DOI : 10.1145/1639714.1639726

L. Wu, L. Yang, N. Yu, and X. Hua, Learning to tag, Proceedings of the 18th international conference on World wide web, WWW '09, pp.361-370, 2009.
DOI : 10.1145/1526709.1526758

Y. Freund, R. Iyer, R. E. Schapire, and Y. Singer, An efficient boosting algorithm for combining preferences, J. Mach. Learn. Res, vol.4, pp.933-969, 2003.

X. Zhu, W. Nejdl, and M. Georgescu, An adaptive teleportation random walk model for learning social tag relevance, Proceedings of the 37th international ACM SIGIR conference on Research & development in information retrieval, SIGIR '14, pp.223-232, 2014.
DOI : 10.1145/2600428.2609556

C. Wei, W. Hsu, and M. L. Lee, A unified framework for recommendations based on quaternary semantic analysis, Proceedings of the 34th international ACM SIGIR conference on Research and development in Information, SIGIR '11, pp.1023-1032, 2011.
DOI : 10.1145/2009916.2010052

M. Sarwat, J. Levandoski, A. Eldawy, and M. Mokbel, LARS*: An Efficient and Scalable Location-Aware Recommender System, IEEE Transactions on Knowledge and Data Engineering, vol.26, issue.6, pp.1384-1399, 2014.
DOI : 10.1109/TKDE.2013.29

P. Mika, Social Networks and the Semantic Web (Semantic Web and Beyond, 2007.

N. J. Belkin, Some(what) grand challenges for information retrieval, ACM SIGIR Forum, vol.42, issue.1, pp.47-54, 2008.
DOI : 10.1145/1394251.1394261

J. Stoer and R. Bulirsch, Introduction to Numerical Analysis, 2002.

K. Caine and R. Hanania, Patients want granular privacy control over health information in electronic medical records, Journal of the American Medical Informatics Association, vol.20, issue.1
DOI : 10.1136/amiajnl-2012-001023