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Work in Progress

 

You will find here the working papers prepared for a special issue of "La Revue d'Economie Politique" sous le titre "Marchés en ligne et communautés d'agents" (Virtual communities and online markets).

You can access and download the papers (french version) and browse the abstracts (english version).

Présentation du numéro

"Biens informationnels et communautés médiatées" : Michel Gensollen (ENST)

Information goods and online communities
Digitalization and virtualization of information goods gradually moves the value of these goods from their physical layer towards the social process which develop and prepare a demand that suits them best. In the other hand, the ICT (Information and Communication Technologies) are currently challenging the top-down information model, from producers to final consumers, through the mass-media system and the retail network. On Internet, new structures of interaction between consumers (virtual communities) are already shaping effective ways to initiate and develop the demand for information goods. This paper presents three types of virtual communities which jointly play a significant role to develop a bottom-up model : (a) files sharing communities (like Napster), that challenge the top-down editorial model; (b) experience sharing communities (like Amazon.com), that help consumers form an ex ante estimation of experience goods characteristics ; theses communities trigger the value migration from information to meta-information; (c) knowledge sharing communities (like free software user list), that help consumers understand and adapt complex goods to their needs ; these epistemic communities could lead information goods designers to better understand the consumers' usage constraints. These virtual communities are original interaction structures: they are characterized by very weak ties or even no interpersonal relations; they center around an information corpus, built and used by anybody for his or her own sake. The survival of these communities does not depend mainly on the altruism of the participants but on the structure of the corpus (the file sharing utility, the reviews, the forum or the user list, etc.). As a regulation model for final markets, virtual communities could lead to a wider variety and a greater adaptability of end-products.


Communautés d'expérience


"Auto-organisation de la demande : apprentissage par infomédiation" : Nicolas Curien (CNAM)

Demand Self-Organization : Learning through Infomediation
In this paper we analyse a process of demand learning based on "infomediation", i.e. relying upon information exchanges across consumers within Web communities. The characteristics of the supplied good are subject to horizontal differentiation and change over time, so that the buyers' information on available varieties is imperfect at each period. We look for conditions under which infomediation proves able to decentralize efficiently demand segmentation, i.e. leads to welfare maximizing. We compare the output of self-organized infomediation to the ideal benchmark of segmentation under perfect information and we discuss the influence of various parameters, such as : the number of infomediation communities ; the respective weights of advices retrieved on the Web and of external factors in purchase decisions ; the degree of informational externalities across communities.


"Communautés d'expérience et concurrence entre sites de biens culturels" : Marc Bourreau et Michel Gensollen (ENST)

Competition between Online Suppliers of Cultural Goods
We study competition between two online suppliers of cultural goods (like books, CDs, or DVDs), when the suppliers can introduce software tools which allow consumers to search for and evaluate products. Using a sequential entry game, we show that one supplier offers only "star" goods (i.e., the goods whose quality is known by all consumers), whereas its competitor provides only "non star" goods (i.e., the goods whose quality is uncertain). We study the incentives of the suppliers to introduce three types of tools - samples, search tools, and a customer review system - and their effect on the market equilibrium.
Keywords: Cultural goods; Internet; E-commerce; Search.


"Transition vers un marché électronique et communautés médiatées" : Eric Darmon et Dominique Torre (LATAPSES)

From Search to Electronic markets: The Role of Virtual Communities
In this paper, we study the impact of virtual communities together with the transition from traditional (search) to electronic markets. For that sake, we analyse the dynamics of an economy composed of buyer-seller agents trading on these two markets. On the search market, the uncertainty deals with the occurrence of an exchange; on the electronic market, consumers can imperfectly appreciate the qualities of the goods they face to. We first describe the properties of this economy, as agents are not able to learn on the electronic market; we point out the crucial role of the stickiness of the search market and of the exogenous expertise of agents. We then introduce virtual communities. We show that these communities are able to promote the use of the electronic channel. Their welfare impact may be found globally positive although some categories of agents may be worst off. We turn at last to the organisational aspects of such communities. As predicted by intuition, the size of the community has a global positive impact. Besides, according to their composition (both the heterogeneity's degree of the individual expertise and of individual tastes), some types of communities may be found superior in a changing context.
e-commerce - search - learning - virtual communities - coordination - Internet economics


"Communautés de consommateurs et marché infomédié" : Alain Raybaut et Stéphane Ngo-Maï (LATAPSES)

Communities of consumers and "infomediated" market
This paper examines a market where a final good producer, some communities of consumers and an infomediary interact. We distinguish, on empirical basis, two types of distributions for the size of communities, a log-normal law and a power law, and are interested in the viability conditions of the market. The emergence of either distribution is related to the weight of collective beliefs of the consumers. The infomediary collects information upon communities and sells it to the producer. His control variable bears on the number of hyperlinks between communities (connectivity). We compare the viability conditions and show the existence of critical ranges for the equilibrium connectivity associated with optimal behaviors in the two distributions settings.


Communautés épistémiques d'innovation


"Communautés épistémiques: réseaux cognitifs et interdépendance entre les partenaires" : Bernard Conein (EHESS)

Epistemic communities and cognitive networks: cooperation and distributed cognition
The goal of this article is to define the mode of cooperation specific to epistemic communities and to agents involved in the logic of innovation based upon learning and exploration. The notions of epistemic community and cognitive network are used to characterize a species of collective action and mode of cooperation involved in use of the internet. However, I argue that the terms 'community' and 'cognitive network' should be restricted in their use. Close examination needs to precede labels. I also argue for a full recognition of the cognitive properties involved in knowledge exchange. Some modes of cooperation are efficient means for knowledge growth. Internet based technology and Open Source architectures provide a powerfull scaffolding for cooperation because they are both social tools and knowledge facilitators.


"La régulation de la connaissance : arbitrage sur la taille et gestion aux frontières dans la communauté Debian" : Nicolas Auray (EHESS)

The regulation of knowledge: size and scope control for the Debian community
The epistemic communities are confronted with a recurrent problem : they must regulate their scope, so as to arbitrate between the club effect and the congestion effect. This compromise integrate actually a complex plurality of regulation choices. What should be the scale of the openness for the new entrants ? How to proportionnate, for each developper, the time allowed to select the applicants and the time allowed to send an advice to the community ? How shall the member of the community share out his effort between assistance for newbies and cooperation amongst experts ? The hypothesis of the paper is that the caracteristics of the regulation depends on the cognitive content of the flow of ideas. It is with a sociological analysis of a complex community that the article tries to answer to those questions.


"Existence, stabilité et efficacité des communautés épistémiques" : Nicolas Curien, Gilbert Laffond, Jean Lainé, François Moreau (CNAM)

Existence, stability and efficiency of epistemic commmunities
The model presented in this paper separates two stages of labour within an epistemic group, such as an open-source community : a first stage is devoted to project design and it generates increasing returns to scale with respect to the community size, due to a club externality specific to creative activities ; then, a second stage is devoted to implementing the epistemic system and it exhibits decreasing returns to scale, incurred when integrating individual inputs into a consistent collective output. We show that, depending on exogeneous factors (club externality, integration level of output, project resistance to implementing, users' preferences between system capacity or interoperability), an efficient community may be either degenerated and restricted to a single agent, or it may extend to the whole background population, or its size may be bounded and greater than unity. Now, the optimum cannot be easily decentralized through individual behaviour, because of a stability/efficiency dilemma which can better be solved through an authority controlling entries in the community, rather than by adopting an allocation rule of common gains, a result consistent with empirical evidence from the open source world.


Communautés épistémiques de production


"Relations inter-entreprises et communautés médiatées: une analyse préliminaire" : Richard Arena (LATAPSES)

Inter-Firm Relations and Virtual Communities: A Preliminary Analysis
The purpose of the contribution is the investigation of the analytical relations which could allow the extension of the scope of the concept of virtual community from consumers/internet -users to firms/internet users. The temptative answer to this preoccupation is given thanks to three steps. The first part of the paper is supported by the existing literature related to the emergence and working processes of virtual communities formed by individual agents within a knowledge-based economy. This literature permits to point out the basic logical criteria by which communities can be defined and characterised in real economies. The second part of the paper utilises the literature focused on inter-firm relations to try to find in it tools which could permit to assimilate firm communities to a specific form of these relations. The last part of the paper checks if it is possible to extend the basic logical criteria pointed out in the first part to the case of firm virtual communities. The main result of the paper is that such communities might exist and that they correspond to some precise forms of inter-firm cooperation.


Knowledge and social interactions in on-line communities
How could we understand community usages of internauts ? In order to respond to this question we go back to two literature areas : Marketing and Knowledge Management, as they have started to analyse the cognitive impact of communities since the eighties (first part). Taking back some results of these works, we offer an analytical model of the on-line behaviour in communities (second part). Our factual study, based on a group of leader users, leads us to identify several results (third part). These ones deal with the structural impacts of technical and social networks ; the hybrid aspect of on-line community practices ; the learning dynamics linked with electronic communities ; the identification of the key role plaid by the "frontier-members" ; and, ultimately, the properties of two "ideal-types" of on-line communities.