Earlier quoted context omitted.
That's because making a big pile of money the Silicon Valley way requires two things: a product, and a moat. It's not hard to create an email product, but email moats are hard because it's an anarchist technology by design.
Would you mind explaining what does "a moat" mean in this context?
If you think of your business as a castle, a moat is something that stops others from taking your castle from you. This could be anything from a network effect (Facebook, LinkedIn), economies of scale (Amazon, Walmart), to patents (most biotech companies) to brand (Coke).
The way he put it was something like, "If you gave me 100 billion dollars to take Coke's market, I can't. They've been investing in infrastructure and brand all over the world for decades. Even if I could make a better tasting beverage, people would still buy Coke. They have a moat".
http://www.valuewalk.com/2015/09/warren-buffett-on-economic-...