Often times, because we as writers are typically a one-man outfit, we don't think of the work we produce as part of a brand. We don't think of ourselves as a "brand". Yet each one of us, different as we are, has a particular brand and it's utilizing and promoting this fact that establishes us as separate and unique from our colleagues and competitors.
Danielle Steel has a brand- she has a targeted audience demographic, a certain style, a certain form of content that lets people know this is a 'Danielle Steel' book before even having to look at the author's name; and her brand works for her, doesn't it? (Diamonds and ball gown skirt included.) Every author from Fitzgerald to Stephen King has a brand that makes their work uniquely associated with them. When the authors would switch mediums to do short fiction, journalism or non fiction, these were merely off-shoots of their brand. It's a certain mix of style, standards and expectations that the audience comes to expect. Part of an author's brand includes how they conduct themselves in public- interviews, signings, speeches... Some are extremely private, some cynical, some gregarious, some gracious. How the author presents themselves physically, the manner in which they dress- (creative personas like the gypsy coutured singer Stevie Nicks or all in black Johny Cash)- furniture lines emulate Hemingway's style, Issac Denison's safari style is in high fashion this season. The lifestyle of a writer is another aspect of their brand. Swinging Manhattan, old English fortress or rugged retreat.
In each aspect of yourself that you present, in how you conduct yourself, the ideas/causes you champion or oppose, all of it makes up who you are as a writer. The important factor is to, above all, be yourself and let the distinguishing traits show through. Too many contemporary writers feel the need to self-camouflage and risk being lumped together by genre instead of distinguished by traits as individuals. For your site, your book covers, your correspondence, your public appearances, pull together a comfortable theme that fits you and will have you standing out in the minds of readers, reviewers, editors and publishers.