By David Russell of OptionMonster NEW YORK -- OptionMonster's tracking systems yesterday detected the purchase of 20,000 September 40 calls for 75 cents and the sale of an equal number of September 45 calls for 20 cents. Volume surpassed the previous open interest in each strike, which indicates that new money was put to work. Owning calls locks in the price where the Internet stock can be bought, while writing them obligates the investor to sell shares if they reach a certain level.