"Open source vendors are often asked how they make money if their software is free. Well, believe it or not, open source and profit are not oxymorons. In fact, several open source vendors are making money, growing in size, revenue, installed base, and influence.
"While products, business models, and licenses differ, companies such as MySQL AB (creators of the MySQL database), Sleepycat Software (creators of Berkeley DB and Berkeley DB XML), and Trolltech (proprietors of Qt and Qtopia) are proving that you can take open source to the bank. Cha-ching...!"