It's the truth. Writing more books sells books. Word of mouth from readers sells books. At least in the romance genre, anyway. All this crap people do to push their books down others' throats does nothing except piss off people from all the spam, and get the authors blocked on social media. We talk about this all the time on Facebook. Newbie authors are being told from Lord knows who to do these ridiculous self-promo things and in the end they wind up banned from groups for doing nothing but promo, spamming people, and making an annoying spectacle of themselves.
I've been at this for almost five years now under three different pen names and I can tell you without a doubt, at least from own experience, that the less I shout my books to the rooftops and toot my own horn, the MORE I sell. I TALK to people on Facebook and Twitter. I get to know them as human beings first. I share just enough of my personal life to make me "real" to them, but not enough to be an endless source of drama. I'm actually a very private person.
And I just keep writing. This might not hold true for all genres, but in world where I write, our readers want more books, not drama and endless spam. If they like us, they already know how to find our next releases. They don't need links and excerpts and snippets shoved down their throats all day long. Tease them for sure, but don't overwhelm them with constant promotion.