I hate to see EV continue to use the word luck because it makes me think that he just happened to be there and didn't really do anything. He needs to step up and take credit. Hopefully in #3 he can do that. "Once your lucky, twice your good" (Book title of Sarah Lacy's book about silicon valley's rise)
Once you're lucky, twice you're good. The thing is, Ev did it a LOT more than twice. He started companies and products over and over and over again. Two of them became widely used. One, Twitter, even managed to make money. He was in a good place, at a good time, joined and supported projects that showed promise.
Ev was originally an angel investor in Odeo, then he decided to join and work on it after we'd been at it for about three months. When Apple crushed us with itunes podcasting integration, he and the rest of us were tinkering with ideas. Jack had a good one, and Ev was able to create the space for that idea to grow in to twitter. Is it luck that Ev invested in his neighbor, Noah Glass's startup Odeo? Is it luck that Jack decided to do twitter has his hackday project instead? His previous project was a universal js wrapper to play audio on the web sans flash.
What Ev is really good at is seeing, oh this seems interesting, let's tinker with it and help it grow. He places himself among interesting things and then supports them. He's right for not taking credit, he participated and helped, he was vital, but he wasn't the CREATOR.
Perhaps you're thinking about luck wrong: of course he did things, but people who are looking for credit are probably more likely to make wrong moves than people who are willing to admit that not everything is in their hands.
Luck is way, way more important than most like to admit.
