Again and again, we see that if you're not the customer, you're the product. "Free" usually means, "you're not in charge.", says Godin.
And it's true. If you're using Gmail you're giving them the right to scan your personal mail so they can refine their advertising, if you're using free web hosting you're likely agreeing to receive advertising on the site you don't control, or are restricted on what you can do with it. What freedom are you giving up for a free product?
Of course this applies mainly to software as a service tool that you use, certainly open source challenges this as the Wordpress platform testifies.
The next time you think of using a free tool for your business, consider whether it will mean you are someone else's product and will be actually giving up some of your freedom or whether you want to pay instead to become a customer, and gain the benefits of being in charge that come along with that.