I estimate there are at least 12 Russian trolls (intelligence agents) active on FR. There are several categories of Russian trolls. Some are blatant and easily identifiable. Others are insipid and conduct the classic communist influence operation: demoralization, repudiation, propaganda and reconciliation. The purpose is to accept the propaganda without actually realizing it. This is possible because the focus of interaction is attaining a consensus with the operative over some innocuous point. This redeems the target’s confidence and, more importantly, requires them accept the propaganda -the real purpose of the interaction.
They are very active, and successful, on conservative and conspiracy sites. Some sites may even be run by them.
IMO they are currently running an influence operation to support Russia’s interests in Syria and energy exports to Western Europe. Middle east oil exported into Europe via Turkish pipelines competes directly with Russian oil exports. Qatar, Kuwait, SA and Iraq all want to export to the EU but do not have secure pipeline routes. Imagine that.