I watched this movie from Frontline earlier this afternoon which provides an excellent behind the scenes look at what took place over the last few years with the biggest insider trading names on Wall Street.
The combination of insider trading and high frequency trading put the statistical probability of a day trader sitting at home and beating the market at 0.0%. Stocks should be bought when they are on sale and held until they are expensive. That hold period is usually about 15 to 20 years during a typical secular cycle. For more on high frequency trading see: The World's Largest And Most Dangerous Casino: A Machine Driven Stock Market.
The preview for the movie is below, and you can watch the entire film here: FRONTLINE: To Catch A Trader