This is a Force-Directed Graph based on mbostock's example: http://bl.ocks.org/mbostock/4062045 The data in the graph was taken from http://snap.stanford.edu/data/p2p-Gnutella08.html and contains A sequence of snapshots of the Gnutella peer-to-peer file sharing network from August 2002.
The graph is showing only the first few hundred connections. That is why some of the points are left alone, because it is a partial picture of the data. The data was divided into ~10 groups of close by points. Each group is shown with different colors.