THINKING
ABOUT NETWORKS
Clay
Shirky (clay.shirky@nyu.edu)
H79.2299
-- Tisch 441 -- Thursday 9:30 - 12:00 p.m.
http://itp.tsoa.nyu.edu/~cs97/tan/
Version
1.0 / January 21, 2005
OVERVIEW(Jump to Classes)
Networks
exist in the spaces between things; they are made up not of concrete entities
(computers, people, businesses) but of abstract relations (protocols,
friendships, contracts). We understand intuitively that networked computers
differ from standalone computers, or that a group of friends differs from an
aggregation of anonymous individuals, but describing that difference is hard.
In
particular, networks exhibit emergent characteristics that cannot be explained
by simply examining their constituent parts. People are not like computers, but
networks of people and networks of computers are similar in many ways. It is
the organization of the respective networks that creates those similarities.
Thinking
About Networks is a class about the
structure of networks, and about how that structure affects human experience.
We will focus in particular on two "invisible" networks --
communications networks, and social networks. Communications networks are
invisible in the traditional sense; their inner workings are hidden inside
devices, behind walls and underground, or pass silently through the air. We
will examine a variety of electronic networks -- telegraph, telephones,
internet -- and design philosophies -- client-server, lattice, peer-to-peer --
and explore the ways different networks alter the experiences that are and are
not possible within them.
Social
networks are invisible in a different way; because we are immersed in myriad
social networks -- friends, family, work school -- and because humans are so
natively good at understanding and working in such networks, we don't see them.
We will examine some of the structural elements of social networks, such as
strong and weak ties, clustering, and small worlds networks, to understand some
of the ways that the shape of social networks affects us.
The
goal of the class is to synthesize our observations about these two types of
networks. Technological choices embodied in electronic networks profoundly
affect their social dimensions: Why can we CC people on email but not on phone
calls? How does the one-way network of television differ from the two-way
network of the internet? What effect does bittorrent's architectural
decentralization have on its users? Social choices also affect the design of
technology; resistance to spamming or attempts to hide from the RIAA have led
to several deep technological changes in the design of weblogs and file-sharing
networks respectively, changes that alter the social relations among the users.
The
class meetings will center on discussion of readings and lectures. Outside
class, you will complete two short papers, a mid-term project, and a final
paper or project. The first will compare and contrast real-world networks. The
second will be a proposal for the final project. The mid-term project will
involve designing and implementing a small network (though not necessarily a
computer- mediated one), and describing its effects. The final will be a
project or research interest of the your choice, and will involve designing,
building and describing a network, a visual and descriptive analysis of an
existing network, or a research paper.
GOALS
The
course has three broad goals: at the end of the course, you should be able to
understand the wayss in which both social and technological networks differ
from the sum of their parts; be able to predict (or at least make an educated
guess about) the kinds of emergent properties, both social and technological, a
given network design will exhibit; and be able to design a network that will
exhibit some of these properties.
CONCEPTUAL
MODEL
The
course will progress through 4 phases:
1.
Introduction to Networks
We
often use the word network without defining the term. FedEx, T-Mobile, and
Earthlink all operate networks of one sort or another. What do these different
sorts of networks have in common? What characteristics are common to various
sort of networks? What desirable effects come from organizing things into a
network, as opposed to either more or less rigid forms? What properties do our
various communication networks exhibit? How do they differ from one another?
What strengths and weaknesses arise from those differences?
2.
Architecture and Perception
Why
do networks work? Put another way, what is special about a network, as
different from a mere collection of nodes? Can we even talk about networks as a
distinct thing, since they are, by definition, interconnected collections of
other things?
Networks
exhibit emergent properties, properties which cannot be predicted from merely
examining their component parts, and these properties vary in surprising ways
depending on the size and construction of the networks. What are the rules and
concepts governing these emergent properties? How can we describe them, discuss
them, visualize them?
Humans
both shape and are shaped by networks. We live in them every day, and they
become so completely woven into the fabric of our lives that the technology
becomes invisible, and our primary experience of them becomes social. "Who
said what to whom when" is more important than whether the messages
traveled by email or carrier pigeon.
Yet
the structure of networks does affect the culture that uses them. The kinds of
conversations people have via snail mail differ significantly from the conversations
they have in email; talking on the phone is very different than
"talking" via IM; group conversations that take place in communities
like Metafilter are very different from those that take place on irc and
different again from mailing lists, in large part because the technology shapes
the culture.
What
is the feedback loop involved here? How do networks affect the social lives of
people that use them? How do the users affect the design and deployment of
those networks?
4.
Open Problems
Over
the centuries, networks have consistently exhibited effects their designers
didn't anticipate. The internet in particular has been and continues to be a
rich source of these unpredicted effects. This quality, coupled with the
rapidly growing size and complexity of the world's networks, means these
unexpected effects are growing in social and economic importance.
What
are the open issues in network design today? How will decentralized
architectures like peer-to-peer affect the ability of individuals to act as publishers,
and what will the world's professional publishers do about it? How far will the
current revolution in decentralization go? How will we handle network addresses
in the future? What problems do mobile devices create for traditional internet
architecture?
These
are open questions: they don't have easy answers, and are worth thinking about
precisely because we don't know what will happen as the world's networks are
adapted to new uses.
Creating
Networks
In
addition, although this is a seminar, we will be concerned with creating simple
networks, because the actual experience of designing and deploying a network is
too slippery to accurately describe without experiencing it.
To
a first approximation, networks can be defined by describing 3 aspects: nodes,
connections, and contents. The Web and email, for example, use the same nodes
(users computers), but have very different ways of connecting (real time versus
delayed delivery) and very different sorts of contents (request and reply --
"pull" -- for a specific URL versus sending for later delivery --
"push" -- of text messages), which make using the Web so different
from using email.
Students
will design networks with different properties of the nodes, connections, and
contents. These networks can be simulated on a single computer, implemented on
the internet, or even executed in the offline world -- projects using networks
of friends are as valid as projects as those using networks of computers.
GRADING
Class
participation 20%
Papers
30% (15% each)
Mid-term
Project 20%
Final
Project 30%
CLASSES
- SECTION ONE: Intro to Networks
Week
1. What is a network?
What
is a network? What are some examples of historical networks? What are some
examples of modern networks? What effect do networks have on our lives?
Why
does this matter? What are the differences between thinking about unconnected
groups of entities -- people, devices, companies -- and thinking about those
same entities within a network? For people who use computers and other
networked devices, what effects do the networks we use have on our perception
of the world?
Assigned
Readings:
The
Victorian Internet (Handout); Standage, Tom; ISBN: 0425171698
Death
and Life of Great American Cities (Handout); Jacobs, Jane; ISBN: 067974195X
Week
2. Historical communications networks: mail, telegraphs, telephones.
Networking
to 1969. How have networks developed over time? What features are common to all
networks? What have the significant milestones been in the development of networks?
Can we describe any large historical patterns in the rise and growth of
networks?
How
is our current media environment affected by the technological aspects of
networks? What are the differences between a television network, a telephone
network, and a packet-switched network?
Assigned
Readings:
Inventing the Internet (Handout); Abbate, Janet; ISBN: 0262511150
Hobbes Interent Timeline http://www.zakon.org/robert/internet/timeline/
What is the internet? ftp://ftp.isi.edu/in-notes/rfc1462.txt
PAPER
#1 ASSIGNED: "Two Networks" Students pick two networks (Telephone vs
telegraph, FedEx vs Bike messenger, etc) and contrast their structure and use.
~750-1000 words.
Week
3. The Internet, 1969-1999
What
is the internet? What is the difference between analog and digital networking?
What is the difference between packet-switched and circuit-switched networks?
What is a node? A connection? A message?
What
is a protocol? A protocol stack? What are the protocols use most frequently on
the internet?
Smart Mobs
(Handout); Rheingold, Howard; ISBN: 0738206083
"Wired/Unwired:
The Urban Geography of Digital Networks"; Townsend, Anthony;
http://urban.blogs.com/research/townsend-dissertation.pdf
PAPER
#1 DUE
Week
4. Peer-to-peer and Wirelessness: Flexibility and Mobility
Peer-to-peer
technologies, best known from file-sharing, but covering a range of
architectures and uses, provide tools for weaving a large number of small
devices into a fabric of cooperation. What makes peer-to-peer special? How does
it differe form classic Web architecture? Where is it most useful?
The
label "wireless" is a hopeless grab-bag of technologies, from the
short-hop connections of Bluetooth and RFID tags, to communications with
geosynchronous satellites 23,000 miles away. What are the various effects of
doing without wires on portability, flexibility, mobility. What are some of the
long term changes on patterns of living being wrought by those effects?
Assigned
Readings:
Cyber-geography
Dodge, Martin; www.cybergeography.org/
Divided
We Stand? Krebs, Valdis; http://www.orgnet.com/divided.html
Vizster;
Heer, Jeff; http://www.cs.berkeley.edu/~jheer/infovis/final/
SECTION
TWO: Architecture and Perception
Week
5. Visualizing Networks
What
is "information space"? How can you visualize an N-dimensional
network in 2D space? 3D space? What visual tools and techniques are there for
representing networks? How does the material used to represent a network affect
the representation? When representing something as abstract as a network, what
information about a network is it vital to represent? What information is it
vital to ignore?
Assigned
Readings:
Linked
(Handout) Barabasi, Albert-Lazlo; Perseus Publishing 2002; ISBN: 0738206679
Six
Degrees (Handout); Watts, Duncan; ISBN: 0434009083
MID-TERM
PROJECT ASSIGNED: Design a network. Chose a networking task (getting a message
from point A to point B; request and deliver a file; create real time
conversations; etc) and explain how you will design and implement this network.
Week
6. Mysteries of Scale: Metcalfe, Reed, Barabasi, Watts
How
does scale change network architecture and design? What changes when a network
encompasses a large number of nodes (N > 10,000)? What are the strengths and
weaknesses of different network topologies? Is there an ideal network topology
for large-scale networks, and if so, what characteristics does it have?
IN-CLASS
DISCUSSION OF MID-TERM NETWORK PROPOSALS
Assigned
Readings:
The
Tipping Point (Handout) Gladwell, Malcolm; ISBN: 0316316962
SECTION
THREE: Networks and Culture
Week
7. MID-TERM PROJECTS DUE - In-class discussion
Communities, Audiences, and
Scale; Shirky, Clay; http://shirky.com/writings/communties_scale.html
We
the Media; Gillmor, Dan; http://www.oreilly.com/catalog/wemedia/book/ch01.pdf
Week
8. Network Effects and Theories of Media
Theories
of media are in part theories of networks -- how and under what circumstances
communications happens. the 20th century was characterized by broadcast media
of an unprecedented scale, but most of the new networking tools invented in the
last 30 years have not adhered to the broadcast model. How can our
understanding of networks improve our understanding of media?
Assigned
Readings:
"Social
Capital"; Smith, Mark K.; http://www.infed.org/biblio/social_capital.htm
"Lessons
from Lucasfilm's Habitat"; Morningstar, Chip and Randall Farmer; http://www.fudco.com/chip/lessons.html
"Autistic
Social Software"; boyd, danah; http://www.danah.org/papers/Supernova2004.html
Week
9. Social Networks and Social Capital
What
is a social network? What social networks do you live in? How do social
networks use technological networks? How do social networks affect
technological network design? What are the social effects of privacy, secrecy,
anonymity, security, reputation in a mediated setting?
Assigned
Readings:
The
Wisdom of Crowds (Handout); Surowiecki, James; ISBN: 0385503865
"Folksonomies
- Cooperative Classification and Communication Through Shared Metadata";
Mathes, Adam;
http://www.adammathes.com/academic/computer-mediated-communication/folksonomies.html
"Terbo
Ted"; http://www.terboted.com/txt/fiendster_story.txt
Week
10. Collaborative Filtering, Folksonomies, and Decentralized Information
Gathering
How
can groups of users create value for themselves and one another without formal
institutional support, and without collaborative infrastructure? What is the
value of tools that extract data from group actions? What are the pitfalls from
trying to read the group mind?
Assigned
Readings:
Field
Observations: Study user groups on Flickr, Dodgeball, FoundCity, and Platial
SECTION
FOUR: Open Problems
Week
11. The Return of the Real
After
almost 30 years of assuming that virtuality is the logical endpoint of human
use of networks, the real world is re-entering the picture, with services that
emphasize or rely on physical proximity coming to the fore in various ways,
exemplified by sites like MeetUp, dodgeball, and Flickr. What is driving the
increasing overlap of the formerly distinct categories of virtual and real, and
what are some likely future developments.
Assigned
Readings:
"Worse
is Better"; Gabriel, Richard; http://www.jwz.org/doc/worse-is-better.html
"The
Cathedral and the Bazaar"; Raymond, Eric; http://www.firstmonday.dk/issues/issue3_3/raymond/index.html
Week
12. Open Issues in Network Design
Networking,
2005-?: Present state and future directions
What
is the current state of network science? Of network technologies? How are our
various technological and social networks likely to intersect in the future?
Fuse? Clash? What are likely areas of fruitful work in the near term? In the
long term?
Assigned
Readings related to guest TBA
Week
13. Guest Lecturer TBA
Guest lecturer from an organization working at the overlap of social and
technological networks.
Week
14. IN-CLASS CRIT OF FINAL PROJECTS:
Readings
related to open issues TBA