This is an old one -- "old" being 2014 -- but The New Yorker tweeted it out recently, so it caught my attention.
Margaret Talbot caught up with John Green on the eve of the opening of the movie version of his book "The Fault in Our Stars":
Publishing executives talk about successful books as if they were lightning strikes, but the popularity of “The Fault in Our Stars” was no accident. Nerdfighters, who by then numbered in the millions, were evangelical about it, tucking notes into copies of the book and encouraging readers to join their movement. In fact, “The Fault in Our Stars” reached the No. 1 position on Amazon six months before it was published, when Green announced its title online. Many authors do pre-publication publicity, but Green did extra credit: he signed the entire first printing—a hundred and fifty thousand copies—which took ten weeks and necessitated physical therapy for his shoulder.
I actually somehow had no idea about Green's massive YouTube following leading up to his writing success. But I love the concept of the multi-pronged/multi-channel approach in our current day and age. To that end:
In a different era, “The Fault in Our Stars” could have been that kind of cultish book. For many young people today, however, reading is not an act of private communion with an author whom they imagine vaguely, if at all, but a prelude to a social experience—following the author on Twitter, meeting other readers, collaborating with them on projects, writing fan fiction. In our connected age, even books have become interactive phenomena.
Again, this is from 2014, but if anything, it seems even more applicable now. (Aside: it's still ridiculous that we have this preference to read recent articles versus old ones, which may be just as good, if not better...)