Oprah (the finance hacker) Winfrey just bought 10% of Weight Watchers and took a seat on the board.

What makes this a hack is she not only bought a company on the cheap, she did it when 50+% of the company's shares had been sold short by the investing public.

Normally, Oprah only gets a benefit from investors copying her investments. In this case though, the same time that investors are copying Oprah's move and buying shares, the shorts are also stampeding to exit their positions.