At any of the RWA national conferences I attended, one of the most exciting parts was the "goodie bag" handed out at registration. These tote bags, usually with the conference logo blazoned on the front (along with some bookseller's ad copy) were crammed full with lots of freebies, especially books. This was a good place for publishers to unload several hundred copies of remaindered paperbacks or new releases they were hyping. The 1991 conference in New Orleans brought us all a big surprise, and I do mean big. Ed Sullivan type really big. A gorgeous, fat hard cover novel by an author none of us had ever heard of: Outlander, by Diana Gabaldon.
There was no hype with it. As far as I know, Gabaldon was not even a member of RWA at the time. She did not speak at the conference, and her publisher provided no other advertising information. We wondered what the heck was going on, that the publisher would hand out 1500 or so free copies of what looked to be a very expensive book.
A year or so later, many of us received free copies of the first sequel, Dragonfly in Amber. Again, that was it, the book and nothing more. By then my daughter had read Outlander and loved it, so I gave her both books. She still has them to this day.
No one was asked to review the books, like them on Facebook, upvote them on Amazon, retweet their praises or downvote any trolls who didn't love them. Obviously not, because there was no Facebook or Twitter. "The web" was still four years in the future.
So how did the Outlander phenomenon develope without the aid of cyber hype?
Very simply: Gabaldon wrote a book, told a story, created characters that readers cared enough about to tell their trusted friends.
Nothing, absolutely nothing, sells a book like the book itself.
As I wrote elsewhere and can't repeat often enough:
To parody the credit card commercial:
Review swap from fellow author? Free
5-star review on Goodreads? $5
Review and "Verified purchase" on Amazon? $10
Honest review from a genuine reader who tells her friends how wonderful your book is?
You can buy all the Goodreads reviews and Facebook likes and Amazon upvotes and retweets and pins you want; you can't "buy" readers.
They aren't for sale at any price.
Write a book they love, however, and they'll pay you.