Oh, but there's several shades of grey. Take running friendica or diaspora on your own webspace, for example. You're a customer to your webhost, but the software is free. Well, it does have the cost of being kinda slow or hard to set up respectively, but still.. there are public pods you can use and donate to, and where the product is mostly the warm fuzzy feeling people get from doing the right thing. I think you are underestimating human generosity and inventiveness.. shop around!
My definition of a customer is someone who pays me.
Someone using a free service is a user, they may not necessarily pay.
Didn't mean to come across as underestimating human generosity, I very much believe in keeping kindness, goodness and giving fashionable, but in money, the context of a business, is largely it's bloodflow.
In the real world, things cost money for businesses to stay open and sustainable.
I'll say it again, in a free system, we are the product that's sold to advertisers.
If I had to pick one, I'd like to be able to pay for such an experience. It's preference and I look forward to seeing how it goes.