On the one hand, I think that native advertising is real-timey (even if the impression wasn't bought on an exchange) because if the ad blends with the surrounding content well, the user "consumes" the ad in a different, natural, and real-time way. So to me, native advertising done well counts as real-time from the consumer point of view.
On the other hand, to all the players (read: you), maybe native shouldn't be considered real-time unless it's traded on an exchange. What makes it different than a traditionally served ad? Sure, the publisher and advertiser had to work to get the ad to look like an "advertorial," but there's nothing real-time about that.
native advertising is intended to blur the line between content and advertising, it has certainly blurred the lines of where it belongs. Then again, perhaps it's fruitless to try categorizing native
advertising; maybe it really is its own thing. What do you think?