  There are different definitions of what a troll is. Certainly, a troll can be
somebody who teases people to make them angry, or somebody who offends people,
or somebody who wants to dominate any single discussion, or somebody who tries
to manipulate people's opinion (sometimes for money), etc. The last definition
is the one that dominates the public discourse in Bulgaria and Eastern Europe,
and this is our focus in this paper. In our work, we examine two types of
opinion manipulation trolls: paid trolls that have been revealed from leaked
reputation management contracts and mentioned trolls that have been called such
by several different people. We show that these definitions are sensible: we
build two classifiers that can distinguish a post by such a paid troll from one
by a non-troll with 81-82% accuracy; the same classifier achieves 81-82%
accuracy on so called mentioned troll vs. non-troll posts.
