Narrative techniques come in and out of fashion. First person point-of-view is the most obvious example. If you remember any one line of Jane Eyre, it’s most likely Reader, I married him..
That particular example also uses a technique which you’ll see less often — breaking down the fourth wall. Which means, simply enough, that the narrator looks right at the reader and consciously addresses that person.
This is done most often on stage, and when it’s deftly handled, it adds a whole new dimension to the story. The audience becomes complicit, in a way, drawn into the story itself. Of course, this technique works especially well for stage plays because the audience really is sitting right there,; there’s a real energy, a palpable energy, flowing back and forth.
In England there’s a kind of stage play I have never experienced here in the states. A pantomime is a play for children, with a lot of interaction between players and audience built in. (Wikipedia has a good overview of how pantomimes work, here.) I’ve seen a couple of these — Frog & Toad, and The Ugly Ducking, and I have rarely enjoyed a theater production so much. Kind of like going to a midnight screening of Rocky Horror Picture Show, but with a happier edge, and sometimes even wackier bent. Kids and adults seem to enjoy pantomimes equally.
If an author wants to break down the fourth wall in a novel, the easiest way is with a first person narrator who tells his or her story to the reader directly. This is not done very often. More usually the primary character is talking to another character within the story. In third person narratives it’s even less common to have a story narrated directly to the audience. John Fowles managed it in The French Lieutenant’s Woman by means of footnotes. He uses the space at the bottom of the page as a kind of parlor where he comes to talk to the readers about the story as it unfolds. I remember an almost visceral shock when I first read that novel and came across a footnote. Being allowed into the author’s creative process in that way jolted me. It wasn’t instructive in tone — no “observe this, reader” but collaborative: this character insists on going down to the Cobb, though I had no intention of her going there.
You don’t see the footnote-as-parlor approach very often. My guess is that most authors are afraid of it. I personally love the idea, but it also scares me. If I put that door at the bottom of the page, what kind of complications might ensue? Maybe you, the reader, will use it to creep into the story.