I suppose some of it is due to craigslist being around for 30+ years. At $25-$30 million a year, it adds up over time. And then if he invests most of it, 30 years of compounding interest does the rest.

Yeah, and investing during the last 30 years would yield incredible results even if you are lousy at picking stocks. And of course, if you'd put even a tiny bit into BTC, you'd have even more.