In a research paper from June 2007, titled "Worldwide Buzz: Planetary-Scale Views on an Instant-Messaging Network (PDF)," Eric Horvitz of Microsoft Research and Jure Leskovec of Carnegie Mellon University analyzed 30 billion conversations among 240 million people using Microsoft Instant Messenger in June 2006. It turned out that the average path length, or degree of separation, among the anonymized users probed was 6.6.

Six degrees of separation posits that a person is a step away from people they know and two steps distant from people known by the people they know--thus the magic number six.

The dataset contains summary properties of 30 billion conversations among 240 million people. From the data, we construct a communication graph with 180 million nodes and 1.3 billion undirected edges, creating the largest social network constructed and analyzed to date.