  Bitcoin-otc is a peer to peer (over-the-counter) marketplace for trading with
bit- coin crypto-currency. To mitigate the risks of the p2p unsupervised
exchanges, the establishment of a reliable reputation systems is needed: for
this reason, a web of trust is implemented on the website. The availability of
all the historic of the users interaction data makes this dataset a unique
playground for studying reputation dynamics through others evaluations. We
analyze the structure and the dynamics of this web of trust with a multilayer
network approach distin- guishing the rewarding and the punitive behaviors. We
show that the rewarding and the punitive behavior have similar emergent
topological properties (apart from the clustering coefficient being higher for
the rewarding layer) and that the resultant reputation originates from the
complex interaction of the more regular behaviors on the layers. We show which
are the behaviors that correlate (i.e. the rewarding activity) or not (i.e. the
punitive activity) with reputation. We show that the network activity presents
bursty behaviors on both the layers and that the inequality reaches a steady
value (higher for the rewarding layer) with the network evolution. Finally, we
characterize the reputation trajectories and we identify prototypical behaviors
associated to three classes of users: trustworthy, untrusted and controversial.
