Now here's a cute top 10: The Defining Moments in Digital Culture [via Sore Eyes]. The earliest moment is 1996, so we're not talking ultimate cause here, more individual events representing waves of cultural properties (um, so not even proximate causes then) of recent history. Entertaining. And I'm not sure how far this can be traced back - from Steal These Graphics and View Source to the listings in the early computer magazines and the distribution of the source code of Unix - but the idea that all this stuff is only bytes afterall, you don't need an expensive factory to manipulate them, and as such anyone can do it, so share the code and teach your peers. That's pretty defining.