Synchronicity kicked in the same day you asked me what it meant to me, personally. I've come across several references to it in my environment because I've been sensitive to it, and it's been simmering.
I found a deep resonance in the idea that a black swan is 'not possible' proven false. A black swan destroys assumption and is the great shaker that moves society along. For better and/or worse, they're the systemic shock that brings change, and they're rare.