zlacker

In my case, it was seeing the photos of Comet Shoemaker–Levy 9's [1] impact with Jupiter on the web very soon after the impact date (latency was but a few days if memory serves, date was July 1994).

[1] https://en.wikipedia.org/wiki/Comet_Shoemaker%E2%80%93Levy_9

>>pwg+(OP)
There were some earlier moments for me as well.

Being impacted by the Morris Worm, and having a (text-based) copy of the Pons-Fleischman paper, both circa 1988, via the uni Unix server, was pretty cool.

But Chelyabinsk was a massively-shared instance, where a random news event in a place that was absolutely not a media centre, was still accessible in very short order with multiple coverages.

Sci-Hub / LibGen give a similar feeling, though in a different sense. Wells's World Brain and Bush's Memex, delivered. Even if the Establishment is being dragged kicking and screaming.