Frequently agents will tell writers, nonfiction writers most specifically, that they need a platform. But what is a platform?
A platform is needed for non-narrative nonfiction. This is nonfiction in which your readers expect you, as the author, to have a certain level of expertise. If you're providing advice on anything—how to achieve happiness, credit repair, parenting, wart removal, movie suggestions, cooking, sleeping, eating, shopping, business start-up—you will need a platform. Heck, sometimes you will even need a platform for memoirs and humor, but not always.
So what is this elusive platform? Let me first tell you want it's not. A platform is not your credentials. It has nothing to do with your degree or degrees, or the level of respect your colleagues have for you. A platform is your name recognition on a national or international level. It's how well you can sell books simply because you have a following.
A platform is your national newspaper column, your television show on NBC, your regular appearance as an expert on radio, TV, or a major website, like theknot.com. A platform means you have thousands of Twitter followers, a blog with thousands of readers, and you get major attention for those things or have received major attention for those things through other outlets.
In other words, a platform means that thousands of people you don't know know you and would buy your book because they know you.