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E-commerce, two-sided markets and info-mediation


  • Alexandre Gaudeul

    (University of East Anglia - Norwich and ESRC-CCP)

  • Bruno Jullien

    (IDEI - GREMAQ - University of Toulouse)


Participants in a market, buyers and sellers, may need the service of an intermediary who will put them into contact and give them information about their potential trading partner. The intermediary chooses what price it will charge to each side to have access to its service. It also chooses what information it will reveal, for example to the buyer about the value of the seller’s product. In a market with network externalities, it would be optimal that everybody had access to the other side, as each side wants as many agents from the other side to be present as possible. This is however not feasible as the intermediary must charge positive access prices if it is to make any profit. In a market with asymmetric information, it would be optimal that all information about the buyers’ and sellers’ valuation for the traded product be available, but the intermediary will want to conceal or manipulate that information to increase its profit. The paper examines in the first part how network externalities play out in the intermediary’s access pricing strategies in both a monopoly and a competitive setting. In the second part, the paper shows how the intermediary will strategically manipulate and conceal information to extract the surplus from trade in the market it intermediates.

Suggested Citation

  • Alexandre Gaudeul & Bruno Jullien, 2005. "E-commerce, two-sided markets and info-mediation," Industrial Organization 0503014, EconWPA, revised 05 Apr 2005.
  • Handle: RePEc:wpa:wuwpio:0503014
    Note: Type of Document - pdf; pages: 30

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    References listed on IDEAS

    1. Masahiro Okuno-Fujiwara & Andrew Postlewaite & Kotaro Suzumura, 1990. "Strategic Information Revelation," Review of Economic Studies, Oxford University Press, vol. 57(1), pages 25-47.
    2. Alexandre Gaudeul, 2004. "Internet Intermediaries' Editorial Content Quality," Industrial Organization 0409005, EconWPA.
    3. Mark Armstrong, 2006. "Competition in two‐sided markets," RAND Journal of Economics, RAND Corporation, vol. 37(3), pages 668-691, September.
    4. Guerra, G.A., 2001. "Certification Disclosure And Informational Efficiency: A Case For Ordered Ranking Of Levels," Economics Series Working Papers 9964, University of Oxford, Department of Economics.
    5. Caillaud, Bernard & Jullien, Bruno, 2001. "Competing cybermediaries," European Economic Review, Elsevier, vol. 45(4-6), pages 797-808, May.
    6. Strausz, Roland, 2005. "Honest certification and the threat of capture," International Journal of Industrial Organization, Elsevier, vol. 23(1-2), pages 45-62, February.
    7. Josh Lerner & Jean Tirole, 2004. "A Model of Forum Shopping, with Special Reference to Standard Setting Organizations," NBER Working Papers 10664, National Bureau of Economic Research, Inc.
    8. Michael R. Baye & John Morgan, 2001. "Information Gatekeepers on the Internet and the Competitiveness of Homogeneous Product Markets," American Economic Review, American Economic Association, vol. 91(3), pages 454-474, June.
    9. Albano, Gian Luigi & Lizzeri, Alessandro, 2001. "Strategic Certification and Provision of Quality," International Economic Review, Department of Economics, University of Pennsylvania and Osaka University Institute of Social and Economic Research Association, vol. 42(1), pages 267-283, February.
    10. Crawford, Vincent P & Sobel, Joel, 1982. "Strategic Information Transmission," Econometrica, Econometric Society, vol. 50(6), pages 1431-1451, November.
    11. Khalil, Fahad & Lawarree, Jacques, 1995. "Collusive Auditors," American Economic Review, American Economic Association, vol. 85(2), pages 442-446, May.
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    Cited by:

    1. Polanski Arnold & Cardona Daniel, 2012. "Multilevel Mediation in Symmetric Trees," Review of Network Economics, De Gruyter, vol. 11(3), pages 1-23, September.
    2. Wataru Tamura, 2013. "Auction Platform Design and the Linkage Principle," CARF F-Series CARF-F-330, Center for Advanced Research in Finance, Faculty of Economics, The University of Tokyo.
    3. Weyl, E. Glen, 2008. "Monopolies in Two-Sided Markets: Comparative Statics and Identification," Department of Economics, Working Paper Series qt69c9c56z, Department of Economics, Institute for Business and Economic Research, UC Berkeley.
    4. E. Glen Weyl, 2010. "A Price Theory of Multi-sided Platforms," American Economic Review, American Economic Association, vol. 100(4), pages 1642-1672, September.

    More about this item


    Intermediation; internet; asymmetric information; information goods; network effects; two sided markets; matching.;

    JEL classification:

    • D4 - Microeconomics - - Market Structure, Pricing, and Design
    • L1 - Industrial Organization - - Market Structure, Firm Strategy, and Market Performance

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