Well, not sure what the OP is suggesting but your content is definitely a product that is attract other users to also pay.

Maybe, if he turns it in this way. I was however referring to what Apps.net says on their about page: https://app.net/about/

"We are selling our product, NOT our users.

We will never sell your personal data, content, feed, interests, clicks, or anything else to advertisers. We promise."

Yet if there was no content, there would be no product... so they are selling your content.

Which means they are just lying in their about page.

"to advertisers" are the important words to note in their claim.

Yes.

Can you illustrate this in direct relation to App.net?

As already mentioned above: their are probably not selling directly your information (in the sense of these days revelations), but they are selling their product because of your content. Simple network effect: the more people there are, the more valuable their application is, the more traction it gains toward new users, the more new users there are.

Making money through you. (Like all user-generated content websites)

That parently isn't the same as selling advertisers information. Nor is it the same as tracking and selling that to advertisers. It's entirely disingenuous to suggest so.

The maxim is 'if you're not the customer, you're the product' not 'If you're not the customer, you're the product we sell to advertisers.'

It's a pithy quote and nothing more, one I can disprove handily by pointing at any number of completely free, donation based services online.

You are not being "sold". That entire line of thinking is intellectually lazy and meant to provoke an emotional response. I wish people would stop it.

Absolutely agree, it's a terrible phrase.

No, it's disingenuous to suggest YOUR content is unrelated to the value of THEIR product.

A reasonable analogy would be conferences, are you paying for the venue, or the access to other people/speakers? does that mean the people/speakers are the product?

My contribution being of value to the site is one thing. Tracking that contribution and using it to target advertising is a completely different thing. Suggesting otherwise, as you and others appear to be doing, is deliberately disingenuous.