Although knowing one's audience is separate from motivation, it can lead into motivation. For example, a writer knows a certain genre is a hot-seller, thus they are motivated to write and capitalize on the momentum. It might sound like a generalized statement, but it is played out in reality.
In non-fiction, no books grab more attention than celebrity or politician tell-alls. The marketing plan can include words like unauthorized biography or controversial. These buzz words are meant to create curiosity and interest. Unfortunately, these books soon lose their allure and go into the discount bin a few months after release, which is why there is a continuous stream of celebrity/politician book du jour. Some biography authors thrive on this wave and ride it all the way to the bank, their motivation for rushing to dig up dirt and put it in print. One only has to look at the news to see the unraveling of Charlie Sheen and chaos that is Linsday Lohan, of which books are already in the works for next year release. An honest biographer will take years to compile a book and not go the way of the National Enquirer or Star Magazine for quick money and turn-around. If you see a celebrity biography endorsement next to aliens with three heads sending greetings to earth, run away!!!
Now there are those driven by noble motives to provide helpful non-fiction books based upon their harrowing or abusive experiences. Sadly, some are so anxious for this, they either by-pass a traditional publisher or get so frustrated by the process they rush to self-publish. This takes the risk of being lost in the shuffle and their stories not seeing the light of day. This isn't a slam against self-publishing, I'm an indie author. Rather to say, if such a story is worth telling, get the right help so more people can benefit.
Perhaps some of the most annoying non-fiction books are those hawking promises to help people gain wealth and fame. We've seen them, those touting immediate success if you buy the book and follow the prescribed program. Sell 1 million books in a month! Really? NOT.
Now, I don't know Amanda Hocking, nor have I read her book, but she's made a splash by becoming an e-book millionaire sensation for selling at 99 cents. Why? What motivated her to sell the book at such a ridiculously low price? That is the first question to pop into my mind when I heard. Was it solely to make fast money? Well, she accomplished that. Gain notoriety for her ingenuity? Well, she accomplished that also. But what about the quality of her writing? I wonder if her book is not worth the traditional price of an e-book - $5.99 - $9.99. What about the rest of us? How will my e-book be receive when I put it up within the month and ask a normal price of $5.99? That's more than 50% off the paperback price, but has she priced me and others out of the e-book market by forcing us to give away our books or match her price to sell? Whatever her motive, I see a selfishness in her efforts harmful to us indie authors and the publishing industry as a whole.
Like many in fiction, my motive is hidden. Anyone who picks up my fantasy books won't know I began writing for my daughter and how the process turned into an endeavor to help her friends in answering their life questions through story. That's learned by interaction. There are however, fiction motives that are known, like I mentioned at the beginning of the article. Paranormal is now one of the fastest growing genres, especially for young adults. Anyone with a idea can go to Smashwords and publish a story and add to the flood sweeping the market. Unfortunately, this instant ability is one of the detractors to self-publishing and gives fodder to the traditionalists who feed on the quality issue.
Another motive in fiction, and along similar lines as paranormal, is fan fiction. Yes, fan fiction. If I see one more self-published modernized version of Pride and Prejudice I'll hurl my breakfast! These writers don't even change the character names! They follow the same story-line, situations and outcome, only set in their neighborhood. There isn't anything original here. They are merely capitalizing on Jane Austen's accomplishments, but believe it is their doorway into the romance genre. The same can be said for reworking Romeo and Juliet. Very rarely does a fan fiction or modern adaptation become a hit and take on a life of its own. A prime example of this is West Side Story, which is based upon Romeo and Juliet. Leonard Bernstein did such a masterful job of reworking that Tony and Maria have taken on an icon status all their own.
I won't presume to tell someone how or why they should write, that is a personal judgment call. But when I see questionable motives so easily displayed, I don't bother with the book.