But switch online to iBooks or Amazon, and the best-sellers list has a touch more blue to it. Titles such as Dirty Past, Love, Lust & A Millionaire and The Virgin Billionaire dominate.

On iBooks, 87 of the top 150 books are labelled romance and in December, one particular title - Taken Hostage By Kinky Bank Robbers outsold Man Booker-winning novel The Narrow Road to the Deep North.

A mix of R-rated fan fiction, romance and so-called "chick lit"  has found a hungry audience, but why the discrepancy between online and bricks-and-mortar best-sellers?

Discretion, low-cost, and the power of a large and growing fan base is also helping to push the once previously low-profile genre into the open online.

Romance fan Rudi Bremer, 27, says readers are buying online because they often later blog or chat about it with other like-minded fans.

"There is a big, positive community and a lot of the readers are incredibly passionate about what they read and do want to talk about what they're reading," she says.

The pattern is repeated at public libraries, most of which have extensive ebook collections. In 2014, the ACT Library Service reported that romance was the most checked-out genre.

The power of the romance readers rivals the sc-fi crew: the Australian Romance Readers Association hosts annual conferences, plus there are book clubs, book swaps, fan-fiction sites and more blogs.

And you need plenty of books if you're going to blog about them.

For authors who don't even write romance, being added to the category can be a boon to their sales. Melbourne author Genevieve Gannon writes fiction about friendship but was surprised to find her work classified as romance on iBooks.

"I think I was lucky they were labelled in that way, because the romance genre has such a large following," she says. "There are hundreds of bloggers around the world, with thousands of followers who love talking about these books. By sitting in that category I think Husband Hunters and Chasing Chris Campbell were seen by a lot of people who otherwise might never have heard of them."

While some people may scoff at the genre, the popularity of romance is a boon for female writers, who are often overshadowed by their male counterparts.

Multiple reports on literacy awards reveal they are dominated by male writers, often judged by a male panel. A survey conducted in 2013 by The Stella Prize - a female-only literacy award - showed that women were critically under-represented.

Chair of the Stella Prize, Aviva Tuffield, says that gender bias comes into play against romance novels.

"Added to the gender bias is a genre bias where female genre fiction is often dealt more harshly than male genre fiction. Fifty Shades and Twilight have been singled out often as being badly written and made fun of whereas action novels by Lee Child or Matthew Reilly are not," she says.

Michael Gordon-Smith, chief executive of the Australian Publishers Association, said because of the way ebooks are sold - once you purchase one, the seller will instantly recommend other titles "we think you'll like" - and given the appetite of readers, they're more likely to buy them.

"Different genres do better in ebooks; they have been especially good for people who read a large number of titles and especially in romance."

It's yet to be seen whether the ebook success of romance books will translate to bricks-and-mortar success.

It's unlikely the decidedly niche sub-genre dinosaur erotica will take off in any big way - think titles like Taken by a T-Rex or Ravished by a Triceratops.

But Bremer says the power of romance readers to push a previously unheard of novel to the top of the charts should have the rest of the book world take notice.