Would you expect him to do anything else? Invert the question: if you had $500 million cash, would you spend it all on Facebook stock? Or Google stock? Or any one stock? Even for company insiders who really believe in the future of their company, it isn't prudent to hold more than a small fraction of a billion-dollar fortune in one stock, from a purely rational perspective. Of course, the public expects irrationally…
Why can't people just accept that Facebook is a fad?
It does not mean the world is going to end. It's a fad, not a solid company. We went through this before 12 years ago. Eventually the market figures it out. Move on. That's what Thiel is doing.
More fads are around the corner. Investors will keep falling for the same old tricks.
Gates and Ellison are very poor comparisons. Their software was not web-based (=ad-based), their main market was the enterprise and they went to great lengths to create long-term customer lock-in. They began in a different era, and are nothing like Facebook, which is a photo-sharing website that relies on display ads and game-playing "whales" to make money.