An undirected graph of a network of friendship on YouTube.  The
dataset was downloaded on 28th February 2013 from

http://socialcomputing.asu.edu/datasets/YouTube2

The file youtube.edge contains the edge list of the graph.  Each line
represents an undirected edge of the form "u v", which denotes that
the user with ID u is friend with the user having ID v.  If you use
the dataset, please cite the follow papers:

* Lei Tang and Huan Liu. Relational Learning via Latent Social
  Dimensions. In Proceedings of The 15th ACM SIGKDD Conference on
  Knowledge Discovery and Data Mining (KDD '09), Pages 817--826, 2009.

* Lei Tang and Huan Liu. Scalable Learning of Collective Behavior
  based on Sparse Social Dimensions. In Proceedings of the 18th ACM
  Conference on Information and Knowledge Management (CIKM '09), 2009.

Nodes: 1,138,499
Edges: 2,990,443
