Altmetric measurements derived from the social web are increasingly advocated and used as early indicators of article impact and usefulness. Nevertheless, there is a lack of systematic scientific evidence that altmetrics are valid proxies of either impact or utility although a few case studies have reported medium correlations between specific altmetrics and citation rates for individual journals or fields. Finally, the coverage of all the altmetrics except for Twitter seems to be low and so it is not clear if they are prevalent enough to be useful in practice.
F. Kooti, N. Hodas, and K. Lerman. Proceedings of the eighth International AAAI Conference on Weblogs and Social Media, page 266--274. AAAI, AAAI Press, (June 2014)
X. Wen, Y. Lin, C. Trattner, and D. Parra. Proceedings of the 25th ACM Conference on Hypertext and Social Media, page 285--290. New York, NY, USA, ACM, (2014)
S. Wu, J. Hofman, W. Mason, and D. Watts. Proceedings of the 20th International Conference on World Wide Web, page 705--714. New York, NY, USA, ACM, (2011)
E. Bakshy, J. Hofman, W. Mason, and D. Watts. Proceedings of the Fourth ACM International Conference on Web Search and Data Mining, page 65--74. New York, NY, USA, ACM, (2011)
E. Ferrara, O. Varol, F. Menczer, and A. Flammini. Proceedings of the first ACM Conference on Online Social Networks, page 213--222. New York, NY, USA, ACM, (2013)