When I began hearing that I had to have a brand and it is what would sell my books, I wrote some about it here. I had my doubts about the idea as I wasn't that convinced an individual, indie writer would find it that easy to create a brand for themselves.
Now I do know that I have a type of book I write. Even when they are historical, they have certain elements in common. That part sounds like a brand would fit. But I thought about it and realized successful brands of the past were broader than one writer or one company even.
So yeah Wranglers have a brand but they are also part of being jeans. The larger brand is a factor in selling the more tightly defined brand.
In romance writing, the most successful brand out there has been that of publishing companies. First Mills and Boon which was English and published romance novels in paperback, at reasonable prices. That led to Harlequin which was popular enough at one time (not sure about now) that people would subscribe to them and get four of their titles each month. This came no matter who the authors were. Silhouette did the same thing.
Those brands got more defined into like Silhouette Intimate Moments or Harlequin Superromance, etc. etc. Within the refined brand was more details that the reader could expect as to length, sexuality, violence, paranormal, etc. Harlequin eventually purchased Silhouette or merged it or always owned it as I'm fuzzy on details but when I went looking for Silhouette the other day, only one 'brand' was left (I think).
So in this sense, branding helps a reader find the type of book they generally prefer. It now goes over into eBooks and a lot of the best selling romance books are still done by the big publishing houses based on their brand (which is why some of those big publishing houses-- like Harlequin--offer scant eBook royalties to their stable of writers. They know the important name is theirs, not the writer's.
Now how does an indie writer form that kind of brand? I think it takes a group of them, and I have seen some in the western romance field starting this. I have no idea how successfully. But the answer to a brand for a romance writer (or really any other genre) seems to me to be a well-organized group where when a reader sees that brand, they will know what they can expect. Short of a publishing house, can that be done? And if you use a publishing house mentality, pretty soon there is a rigid set of rules where some get excluded based on not fitting in. That puts us back where we have been before eBooks. Good the business end of writing, not so much the creative end.
It's not like I know the answer to this but it's one more aspect of this concept of a brand and how it might be used. I understood some of it when I began the blog-- Romance with an Edge. I thought then that maybe it would draw in other romance writers who also wrote with an edge as I do. Didn't happen. Which led to a blog easier for people to find if they know my name-- Rain Trueax. Which has me still scratching my head for what really works to both encourage writers-- and sell books.