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that will be visible within the context of the Face-
book social network. This platform bases its busi-
ness model around two main features: (i) the
ability to segment the publicity by characterizing
the target audiences as per the demographic in-
formation stored in the users’ profiles (e.g. res-
idence, age, gender or marital status) and (ii)
the viral propagation of the products or brands
by the users’ themselves, grounded on the news-
feed mechanism. Because of newsfeed, every
time a user expresses an opinion about an adver-
tised product, it is automatically communicated to
his/her contacts in the social network. The adver-
tisers pay for each newsfeed message that carries
their products or brands, while benefitting from an
advertising model based on trust, in which their
campaigns are more likely to catch on among the
users for going along with the opinions of some
people they know.
• On the other hand, AdLemons comes as a platform
devised specifically to manage publicity in blogs.
The idea is to enhance the targeting of advertising
by taking advantage of (i) the usually high level of
specialization of the contents appearing in blogs,
and (ii) the consequent formation of communities
of interest around them. The owners of the blogs
benefits from the fees paid by the advertisers in
exchange for offering space for brands and prod-
ucts in their pages.
In spite of their unnegligible advantages, the cur-
rent models of social publicity do not fully exploit the
potential of targeted advertising. In the case of Face-
book Ads, for example, the advertisers can merely
identify target audiences by their demographic data,
obviating such relevant factors as the preferences and
needs that could well be inferred from the users’ ac-
tivities in the social network. It is clear to us that,
having knowledge about the users beyond their per-
sonal data, it would be possible to reach the people
potentially most interested in each type of product in
a more elegant and powerful manner.
Our proposal in this paper has been inspired by
a less sophisticated approach to gather users with a
purchase in mind over the Internet. For many years,
people have resorted to online forums in order to get
in touch with others who could be interested in buy-
ing a number of units of a given product, in order to
get a better price per unit from some provider than
proceeding invidivually. This approach has not been
addressed in e-commerce research for two main rea-
sons:
• First, forums merely provide a rendezvous to
gather a number of purchasers, with neither a
way to ensure that there will be providers in the
position to satisfy their demands, nor to assure
the payment from each one who had in princi-
ple agreed to participate in the batch purchase. In
the absence of such guarantees, it usually happens
that there seems to be a sufficient number of users
to make a purchase, but many of them disappear
when it is finally time to transfer money. This
way, forums turn out to be an unreliable medium
for both consumers and providers.
• Secondly, it is clear that forums leave just too
much work in the hands of the users, since they
have to take the initiative to get together and
manage the whole process of batch purchase (in-
cluding the search for and communication with
providers), interacting actively without any kind
of assistance. Indeed, a similar shortcoming can
be found in AdLemons and Facebook Ads, inas-
much as the advertisers have to define manually
their campaigns by identifying the most suitable
audience segments for each kind of product.
We present a system that addresses the aforemen-
tioned limitations by acting as a mediator between
users and providers for the trading of batches of prod-
ucts over the Internet, taking advantage of the poten-
tial of social networks as a vehicle of trusted public-
ity and a means to gain customer loyalty. The sys-
tem, called Bulker, gathers knowledge about the pref-
erences and needs of the users through the different
social networks in which they participate, in order to
identify the products that best match their interests
and to assist in the formation of groups. It also acts
to locate providers able to offer batches of products
in advantageous conditions for the users, as well as to
control the propagation of publicity through networks
of contacts. Finally, the system includes secure means
of payment in order to guarantee the commitment to
purchase from all the users interested in the batches
in offer.
The overall design and the main features of the
Bulker are described in Section 2. Next, Section 3
presents our plan of development and deployment. Fi-
nally, Section 4 provides a summary of conclusions,
including an outline of the business model envisaged
for commercial explotation.
2 OVERALL DESIGN AND
FUNCTIONALITIES
The Bulker appears as a mediator between consumers
and providers for the trading of batches of products
over the Internet, with a double objective:
• To Search for Customers. A provider registers
BULKER-AMediatorSystemGroundedonSocialNetworksforOnlineTradingofBatchesofProducts
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