During the mid-00s, a lot of bloggers (including myself) wrote about "super-empowered individuals," aka people who had been empowered by technology and globalization to have a vastly disproportionate long-term effect on national or global systems. The term, actually, was ironically coined by Thomas Friedman--a figure who many international relations and national security bloggers (including myself) sometimes mock. The September 11 attacks are seen as the keystone superempowered individual event, because they radically shifted the course of American foreign policy and defense for a decade. To get a feel for how radically things were changed, one need only look at the events of 2001 that preceded it, most notably a Cold War-style scrapup with China over a downed surveillance plane.
The more I've thought about it, though, it seems more accurate that absent the rare 9/11-style event, the only way for super-empowered individuals to really have a strategic as opposed to momentary tactical or operational effect, is to create a cumulative effect on top of a series of existing conditions. One of the biggest myths is that the Afghanistan is the "graveyard of empires," and that stems largely from the Soviet experience in the 1980s. But a bunch of insurgents with small arms and Stingers didn't topple Ivan.
The conditions for the fall of Moscow were present for a very long time. Fabius Maximus once noted that Robert Heinlein had visited mid-century Soviet Russia and saw long-term weakness. If the Afghan War had an effect, it was most certainly cumulative in that it helped aggravate an existing dysfunctional system.
The problem with this is is that determining the "point of inflection" is tremendously difficult. Revolutionaries of various stripes have tried to determine this since the mid-1800s, with varying pseudoscientific methodologies. Few of them predicted that it would be backward, agrarian Russia, not the industrialized West, that would be the first nation to fall to Communism.
And it is likely that any super-empowered individual's cumulative effect on events today will be visible only in extreme hindsight.