Michael Bloomberg built his estimated $16 billion fortune thanks to Bloomberg LP, the financial news provider he founded in 1981. Thirty years later, it is now one of the most lucrative media operations on the planet. Banks and large corporations pay $1,250 a month for each Bloomberg terminal that's installed in its office. There are no discounts available and the company never engages in price negotiations. And while Bloomberg faces competition from the likes of Reuters and Dow Jones, neither company has been able to successfully dislodge the grip that Bloomberg has on the financial media marketplace. No wonder. Getting Bloomberg to cancel your monthly subscription is about as easy as getting Columbia House to stop billing your credit card for those "free" DVDs it insists on sending you every month, even after you've called the 1-800 number a dozen times to complain.