Peer-to-Peer and Social Networks
What is a P2P network
Why study P2P
Twitter
Social Network
Example of networks
Six degrees of separation
Milgram’s experiment
Shortcomings of Milgram’s experiment
Facebook experiment
Erdős number
Kevin Bacon number
Important questions

Milgram’s experiment
Milgram arranged to send 160 envelopes to a group of randomly
selected people from Wichita, Kansas and Omaha, Nebraska.
Each envelope contained the following:

1. A document with the logo of Harvard on it.
2. Name, address and occupation (stock broker) of Milgram’s friend
in Boston, MA.
3. Instructions to get the package to the target person following
specific rules: each person could only send the package
to an acquaintance defined as being on “first name basis”.