See the definition here, dated 26 January 2011, a couple of weeks after Jared Loughner killed six and injured 13:
Stochastic terrorism is the use of mass communications to incite random actors to carry out violent or terrorist acts that are statistically predictable but individually unpredictable. In short, remote-control murder by lone wolf.... It goes downhill from there.
This is what occurs when Bin Laden releases a video that stirs random extremists halfway around the globe to commit a bombing or shooting.
This is also the term for what Beck, O'Reilly, Hannity, and others
"It seems inevitable that rhetoric like [Scalia's] will stir the next Confederate flag-waving zealot to an act of, if not domestic terrorism, at least outrageous revolt. How could it be otherwise?"
I'd call that a fair stab at stochastic terrorism, wouldn't you?