This is going to be wholly anecdotal, but I've begun wondering about the way I hear the expression deployed--in the context of activist concerns, often in forums with the potential to "boost awareness," that signal aim of media of all stripes: "People don't talk about this."
The first question I like to ask is "what do you mean by that?" It's clear off the bat that the assertion is not literal: the person talking is invariably a human, talking at that very moment about this, whatever this is. So one (or both) of two elements is apparently being exaggerated, or defined contextually. That is, either we mean something different here from what we normally understand under the noun "people," or we are hyperbolizing "don't talk."
In the first case, the claim could be rephrased as something like "most people/the right people/those with the public's ear don't talk about this." In the second case, we might imagine: "People don't talk about this enough." And a hybrid allows for the concerns of either version to manifest more strongly, according to the prejudices of the listener: "Those with the public's ear don't talk about this enough." This last statement could be interpreted, depending on one's systemic understanding, to mean either that the "mainstream media" (in my opinion, an increasingly useless phrase) observes a code of silence around the subject, or that the media that does cover it does not receive the exposure it would need to do justice to the subject in the public consciousness.
This is where things get really bumpy for me. On the one hand, media silence is real, and I have seen its effects play out in social situations. If you take a particular interest in an issue that is discussed at length only by special media outlets (“at length” being the operative phrase there, since cursory reporting is responsible for the most dangerous kind of misinformation, the kind that considers itself informed), it is easy to imagine that all those around you are familiar with the discussions to which you have been exposed.
The problem, of course, is that I am falling into the same trap of which I was just so dismissive: I'm imagining "being informed" as a single state, existing in the positive or the negative, and excluding the nuance of the real media environment that we daily navigate. “I am informed,” I think I know, “and my friends are informed,” I necessarily assume, “so we must all have heard the same things.” It doesn't help matters that this is so often true, as when, on a recent trip to Boston, two of my friends and I realized mid-conversation that we were all referring to the same New Republic article without directly referencing it.
Which, finally, brings us full circle: we were talking about punctuation in texting because people, specifically the right people, Ben Crair of the New Republic, who had the public's ear, were talking about it. And yet, we were bringing it up in conversation as interesting because we hadn't previously heard it talked about, because we perceived it as something people weren't talking about. So, even if the claim of under-exposure may in many cases be just, it is equally shrewd on the part of new media rhetoricians to exploit this impulse in their listeners.