We humans love patterns – they're a time saver, so we don't have to make the same decision each time we come across something new. “Look at that big tawny cat,” thought a dimwitted ancestor, “I saw one pounce on and eat a gazelle last month. I'm not a gazelle, so surely the cat won't – AAArrrggghhhh!”
Fiction categories and keywords help us find things. At their best, they help us organize massive amounts of data into usable constructs. They save me, as a reader, from having to read through the first 20,000 words of a novel, only to find out it's not a subject I care for. In the bookstore (online or brick-and-mortar), they help me sail past the stuff that doesn't interest me.
To me as an independent author, however, they feel a bit rigid. One of the reasons I didn't approach a traditional publisher for my novel, Overload Flux, is because it's a science fiction-action-romance, and doesn't fit their standard marketing templates. It's space opera, too, which is another sub-genre that doesn't fit neatly into one of their slots.
Some of the problem, I think, is the restrictions of the physical model don't serve the virtual one. Brick-and-mortar bookstores have limited space, and limited money to invest, so they only buy ten copies of the book, and put them all in one section on one shelf. So my science fiction-action-romance book probably gets shelved in the science fiction because it's cover doesn't scream romance. For one thing, the characters aren't naked. ;–}
In the online world, the bookseller doesn't have to worry about where to put the book, or how many copies to buy; they're selling copies of the file, which they only have to store once. So they can easily afford to put my book in both the science fiction and the romance categories, and furthermore, they can afford to create sub-genres to help readers find books. Amazon allows publishers to specify up to five genres, and good use of keywords gets the book in several more (including space opera). B&N, Kobo, iTunes, and Smashwords don't offer nearly as many categories, and I think they're doing their readers a disservice.
Fiction Category Mayhem
Science fiction romance (SFR) is a relatively new sub-genre. It used to be lumped into the “futuristic, paranormal, and fantasy” category, where you had to wade through the vampire and shifter novels to find it. Some book sellers (cough *B&N*) still have it that way. On the other hand, if you get to the SFR category on Amazon, you'll find an amazing number of books that have no business being in that list. (Note to publishers: Meyer's Twilight series is not SFR, and Garwood's Rebellious Desire, which is a Regency romance, is not even in the same solar system. And sorry, much as I admire Gabaldon's Outlander series, time travel doesn't make it SFR, either.) I like reading SFR, and it's annoying to have to wade through the crap to find the good stuff. I will say that Smashwords is pretty good at showing relevant listings, but has a rather limited selection.
I get why publishers are tempted to put a book in lots of categories, but I think it's the same problem that some authors have in determining their audience. There's this mindset that says, “Pretty much anyone who reads books will love mine!” I hate to be the voice of harsh reality, but no, sweetie, no they won't. For example, I don't read historical westerns. I've tried a few over the years, and they're not for me. Selecting the “science fiction romance” category on Amazon for a western will include it in that list, but chances are, all you've done is annoy me when I'm trying to find Ruby Lionsdrake's next Mandrake Co. book or C. E. Kilgore's next Corwint book, or chance upon a new SFR author.
On the flip side, I understand there are readers who don't want science fiction or fantasy in their romance, or at least think they don't. Linnea Sinclair says she's had lots of people tell her they had no idea they liked SF until they read her books. It's legitimate, I think, to put her books in the science fiction category and in the romance category. Hopefully, her publisher didn't also put them in with the westerns.
Fiction Keyword Quandary
Booksellers don't know how to use keywords. There, I've said it. B&N is especially bad—try searching for “science fiction romance” and see what I mean (Shelley's classic Frankenstein is a science fiction romance?!?). Kobo is better, but not immune (Thoreau's Walden—really?). I can't speak for iTunes (or iBookstore), since I don't use it to find content, and the Web version gives me titles and, occasionally, authors. I have no earthly idea how you browse to find something new to read in Apple-land.
As an aside on keywords, I wish authors or publishers would tell me if I'm going to get a little romance in whatever they want me to read, because these days, I'm more inclined to read it if there is. Usually, though not always, blurbs are pretty good at explaining that. They're less good about sex. I'm happy to read blushing kisses all the way through hot eroticism, as long (A) I'm forewarned, and (B) it furthers the plot. When it's just pasted in so the book can fit in the “erotic” category, I usually skip ahead. It's kind of like old musicals from the 1930s — the plot is chugging right along, then comes to a lurching stop while the leading lady (a soprano, natch) sings a sweet song, then starts up again and goes until the next stop, when the leading man (a tenor, natch) sings a manly song, and so forth. It's worse than riding the local bus at rush hour–it takes two hours to get home.
Adding random keywords or putting the book in all genres doesn't help anyone. Hard SF readers don't like to be offered a gooey-center fantasy when they're looking for a new book to read, and if the blurb and other marketing convince them to buy it, they're going to be mightily pissed. That said, I like cross-genre books where the mystery element, the science fiction/fantasy element, the steampunk and/or the romance element complement one another. See Linnea Sinclair, Ann Aguirre, Eve Silver, Lindsay Buroker, C. E. Kilgore, Sheryl Nantus, Ruby Lionsdrake, Naline Singh, Jennifer Ashley, Meljean Brook.
OK, I've rambled on about this without coming to a conclusion. If you're reading this, maybe you have some thoughts to share in the comments.