I never said that's a bad thing. But at least with the open source software I work with, if you use the software, great. Maybe you will come to me for services later. I wonder how many Debian-involved businesses have such a model.
Paying for media is an interesting exception. Very often for newspapers, etc, you are both buying a product and becoming a product.
But in the end it's a good warning to know the business model of those you get free stuff from.
I pay for cable, yet I still get advertising.
That "not paying means you're the product" is a nice sound bite, but it doesn't actually mean anything.