In the context of mobile advertising, the advertisers are
parties who wish to advertise their products, the publishers
are mobile applications (or their developers) that bring advertisements
to the users. Ad networks or aggregators link the
publishers to the advertisers, being paid by the latter and paying
the former. Tapping on advertisements may lead users to content
on Google Play or to web links. This often happens through a
chain of several web page redirections. We generally refer to
all these URLs in these web page redirections as the redirection
chain and the final web page as the landing page. Ad networks
themselves may participate in complex relationships with each
other. Certain parties, which may be ad networks themselves,
run so-called ad exchanges where a given ad space is auctioned
among several bidding ad networks so as to maximize profits for
the publishers. Ad networks also have syndication relationships
with each other: an ad network assigned to fill a given ad space
may delegate that space to another network. Such delegation
can happen multiple times through a chain of ad networks and
is visible in the redirection chains.