In the immediate aftermath of this morning's devastating earthquake - PPS's network of bloggers rose to the occasion - providing personal and timely reports from various parts of the country
J. Leskovec, L. Backstrom, and J. Kleinberg. KDD '09: Proceedings of the 15th ACM SIGKDD international conference on Knowledge discovery and data mining, page 497--506. New York, NY, USA, ACM, (2009)