review articles DOI:10.1145/2699416 Jacob Moreno’s25 efforts to develop Exploring three interdisciplinary areas and the “sociometry.” Soon thereafter, the mathematical framework offered by extent they overlap. Are they all part of the graph theory was also picked up by same larger domain? psychologists,2 anthropologists,23 and other social scientists to create an in- BY THANASSIS TIROPANIS, WENDY HALL, JON CROWCROFT, terdiscipline called Social Networks. NOSHIR CONTRACTOR, AND LEANDROS TASSIULAS The interdiscipline of Social Networks expanded even further toward the end of the 20th century with an explosion of interest in exploring networks in biological, physical, and technologi- Network cal systems. The term Network Sci- ence emerged as an interdisciplinary area that draws on disciplines such as physics, mathematics, computer sci- Science, ence, biology, economics, and sociol- ogy to encompass networks that were not necessarily social.1,26,35 The study of networks involves developing ex- planatory models to understand the Web Science, emergence of networks, building predictive models to anticipate the evolution of networks, and construct- ing prescriptive models to optimize and Internet the outcomes of networks. One of the main tenets of Network Science is to identify common underpinning principles and laws that apply across Science very different networks and explore why in some cases those patterns vary. The Internet and the Web, given their spectacular growth and impact, are networks that have captured the imagination of many network scien- THE OBSERVATION OF patterns that characterize key insights networks, from biological to technological and social, ˽ Web Science and Internet Science aim to understand the evolution of the Web and the impact of the Web and the Internet on society and the Internet respectively and to inform debates about their future. These and business have motivated interdisciplinary research goals lead to different priorities in their to advance our understanding of these systems. Their research agendas even though their communities over overlap. study has been the subject of Network Science research ˽ Network Science aims to understand the evolution of networks regardless for a number of years. However, more recently we have of where they emerge: the Internet as a witnessed the emergence of two new interdisciplinary network transforming and forwarding information among people and things, areas: Web Science and Internet Science. and the Web as a network of creation and Network Science can be traced to its mathematical collaboration. ˽ Given their intellectual complementarities, origins dating back to Leonard Euler’s seminal work we propose sharing and harmonizing 15 th the data research infrastructures on graph theory in the 18 century and to its social being developed across these three interdisiplinary communities. scientific origins two centuries later by the psychiatrist CREDIT TK 1 COMMUNICATIONS OF THE ACM | AUGUST 2015 | VOL. 58 | NO. 8 AUGUST 2015 | VOL. 58 | NO. 8 | COMMUNICATIONS OF THE ACM 2 review articles tists.13 In addition, the emergence of and sociology as well as computer sci- security, privacy, and resilience. This online social networks and the poten- ence and engineering. A major focus motivates the need for multidisci- tial to study online interactions on a of the Web Science research agenda is plinary research on Internet Science massive, global scale hold the prom- to understand how the Web is evolv- that seeks to understand the psycho- ise of further, potentially invaluable ing as a socio-technical phenomenon logical, sociological, and economic insights to network scientists on net- and how we can ensure it will contin- implications of the Internet’s evolu- work evolution.24 ue to evolve and benefit society in the tion along these principled direc- Web Science6 is an interdisciplinary years to come. tions. Hence, Internet Science is an area of much more recent vintage that Internet Science. The Internet has emerging interdisciplinary area that studies the Web not only at the level of provided the infrastructure on which brings together scientists in network small technological innovations (mi- much of human activity has become engineering, computation, complexi- cro level) but also as a phenomenon heavily dependent. After only a few ty, security, trust, mathematics, phys- that affects societal and commercial decades of Internet development it ics, sociology, economics, political activities globally (macro level); to a is self-evident that if the Internet be- sciences, and law. This approach is large extent, it can be considered the came unavailable, the consequences very well exemplified by the early In- theory and practice of social machines for society, commerce, the economy, ternet topology study.16 on the Web. Social machines were defense, and government would be Interdisciplinary relationships. All conceptualized by Tim Berners-Lee in highly disruptive. The success of the three areas draw on a number of dis- 1999 as artifacts where people do the Internet has often been attributed ciplines for the study, respectively, creative work and machines interme- to its distributed governance model, the nature and impact of the Web, diate.3 Semantic Web and linked data the principle of network neutrality, the Internet and networks in general technologies can provide the means and its openness.14 At the same time, on government, business, people, for knowledge representation and rea- concerns related to privacy, securi- devices, and the environment. How- soning and enable further support for ty, openness, and sustainability are ever, each of them examines how social machines.20 raised and researched as they are of- those actors co-create and evolve in Studying the Web and its impact re- ten at the center of contestations on distinct, unique ways as shown on quires an interdisciplinary approach the Internet.11 The Internet can be Figure 1. For Web Science it is the that focuses not only on the techno- seen as an infrastructure, the social aspect of linking those actors and logical level but also on the societal, value of which must be safeguard- the content with which they interact political and commercial levels. Es- ed.18 It is the infrastructure that en- making associations between them tablishing the relationship between abled the evolution of the Web along and interpreting them. For Internet these levels, understanding how they with P2P applications, more recently Science it is the aspect of communi- influence each other, investigating the cloud, and, in the near future, the cation among actors and resources potential underpinning laws and ex- Internet of Things. It has been ar- as processes that can shape informa- ploring ways to leverage this relation- gued the infrastructural layer of the tion relay and transformation. For ship in different domains of human Internet and that of the Web must be Network Science, it is the aspect of activity is a large part of the Web Sci- kept separately to foster innovation.4 how these entities, when considered ence research agenda. Web Science A recent study7 identified a number to be part of a network, exhibit cer- draws on disciplines that include the of principled directions along which tain characteristics and might ad- social sciences, such as anthropology, the Internet needs to evolve; those here to underpinning laws that can communication, economics, law, phi- include availability, inclusiveness, help understand their evolution. losophy, political science, psychology, scalability, sustainability, openness, However, to understand better the Figure 1. Web, Internet, and Network Science aspects. Social Sciences Web Science People Engineering The content (co)creation, linkage and evolution aspect Web protocols, code and policies Computer Science Government Psychology Internet Science Business Law The information relay and transformation aspect Internet protocols, code and policies Economics Devices Education Network Science Environment Network properties and network evolution Mathematics … 3 COMMUNICATIONS OF THE ACM | AUGUST 2015 | VOL. 58 | NO. 8 review articles similarities and differences between cial scientists were joined by a large these areas and to establish the po- and growing influx of scholars from tential for synergies, a framework for the physical and life sciences who be- a more detailed comparison is needed. gan exploring networks in social sys- tems. This effort was acknowledged A Comparison of All three areas and further catalyzed by the launch Interdisciplinary Areas draw on a number of annual Network Science (NetSci) It takes only a quick read through a conference in 2006, a major infusion short description of each of these in- of disciplines for of funding in 2008 from the Army terdisciplinary areas5,32,35 for one to the study, Research Laboratory for the develop- realize that, to a very large extent, they ment of an interdisciplinary Network all draw from very similar sets of dis- respectively, Science Collaborative Technology Al- ciplines. Venn diagrams that have liance (NS-CTA), and the launch of been used to illustrate the involve- the nature and Network Science in 2013. Clearly there ment of different disciplines in each impact of the Web, was already a community in place, area are indicative of this overlap. For which engaged in interdisciplinary example, psychology and economics the Internet and work long before those initiatives; are considered relevant to Network networks in general one can argue a hybrid