People who are members of the traditional book industry world – publishers, literary agents, and others – have long understood the value of author branding. Cultivating a public profile for authors helps their existing books sell and helps launch any new ones they write. As much as social media today can be a part of an author's public platform, the media still matters a lot. Being interviewed on TV or a highly respected podcast provides an implied endorsement. It's the same to be mentioned in an article on a respected media website or high-profile blog. It means you're a part of the news and taken seriously.
Author branding works hand in hand with book publicity, and an interview or mention in an article often achieves both. A book launch can be the reason to be interviewed, but people in the audience respond to people, not a book. Therefore, the impression you make on the audience is permanent and about you. Even if you're not a natural-born self-promoter, becoming a successful author nearly always involves an element of personal publicity. Also, as you make contacts in the media, they may reach out to you for comments or quotes at other times. They and their audience value your expertise.
Non-fiction authors who have unique expertise in a subject area are often quoted in the news as experts in their field. More than one businessperson has written a book as a way to reach new customers and clients. It's an excellent marketing strategy and one that pays off for years to come. Writing a book is one of the best ways to be regarded as an expert in any field. We've all see authors interviewed on TV talk shows and quoted in the news. If you've had challenges promoting yourself in the past, you'll be impressed by the difference it makes when you become a published (and respected) author.
As much as the internet has altered the media landscape, you'll still see much online content originating in the media. Some of the best things to post on your social media and your author's website are links to interviews and articles where you've been included. Your fans and followers will be interested in watching and reading your appearances, and as mentioned earlier, they will be impressed. Seeing the places where you've been included gives you expanded stature in their eyes and confirms for them the decision to follow you online and potentially buy and read your book. It all works together.