Okay, so maybe they work, but are they dishonest? YES.

I don't think they're dishonest if they're in the context of what someone's actually doing, e.g.

http://pandawhale.com/post/17343/sergey-goes-to-the-2013-vanity-fair-oscar-party-with-glass

If I share a commercial product on Facebook, Twitter, Pinterest, etc., is that authentic, too?

I think so.

Sure, if you don't work for the product's company, are a familiy member or affiliate of the product or product marketing company associated with the product.  

Look, I'm all for guerrilla marketing, but this blending of the line between facts, personal opinion, editorials, advocacy journalism, and advertising is just a little worrisome.  Not for me, as I understand the distinctions, but for the rest of the world. :-) 

I agree that everyone should disclose their relationships with anything they endorse.

On the other hand, if they're endorsing it then clearly they're biased toward what they're endorsing.

So perhaps that's redundant and it's just better to assume a relationship?

Native as "semantically or esthetically adjacent to the main content"?

or

Native as "mimetic"?

Well, there's no good definition of what it means, so I'll go ahead and define it.  "Exactly like content". 

"Awesome advertising is often indistinguishable from great content."

http://pandawhale.com/post/17343/sergey-goes-to-the-2013-vanity-fair-oscar-party-with-glass?comment=51814