Islamic State provokes Russia: speculating on why

It would appear terribly counterproductive for the Islamic State to provoke Russia at a time when they are already facing US airstrikes and a Middle East rallying against them.  Clearly, it is a means of declaring their intent to be a global threat while most would write it off as ambition rooted in delusion.  Still others might even question if the Islamic State is possibly trying to unite Russia and the West against a common threat to foster eventual peace. 

Beyond dismissing this little tidbit of news as a gesture of bravado, there may well be some strategic thinking behind drawing Russia into a fight.  Although Russia may be known for its far more vicious, brutal approach to addressing terrorism, much of which the West would consider just as unacceptable as actual terrorism, Russia is far less capable than the US of leading a coalition of forces  and tactical operations.  

Meanwhile, Russia entering the fight against the Islamic State during a time when the West and Russia are conflicting over Ukraine would create another potential flash point for a world war, thus it would discourage the US from escalating its intervention against the Islamic State.  As such, it would also discourage Russian partners, i.e. Syria and Iran, from indirectly cooperating with the United States, thereby undermining any form of regional cooperation.  

Furthermore, the Islamic State could be turning its attention toward Russia, so Americans no longer see the Islamic State as a viable threat to the West.  Given the release of the videos featuring the gruesome murders of journalists James Foley and Stephen Sotloff were intended to intimidate Americans, such motivations are plausible.  Finally, recognizing the behavior of the Islamic State parallels that of the Mexican drug cartels, it is clear the world can expect increasingly brutal violence from the Islamic State.