He exercised options for $15 each and then sold those options for $29 to $29.90 each. You can see the detailed transactions on this SEC filing, which shows he first exercised 500,000 shares at $15 each on 10/19/2007, and sold them that day and then exercised 250,000 shares at $15 each on 10/22/2007, and sold them that day.
I know that, cuz I bought 740000 Shares from him the other day. Want some? I am giving it for freee. hi hi hi. Sorry. was just feeling bored
When the CEO sells, most investors would take it that the company is not doing as well and the stock price would be heading south. It will be interesting to see how many Google shares the founders sell in the open market.