I sure have.
At first I think, Wow this person is really bright.
And then I think, Hey! Wait a minute. I wrote that!
To set the record straight, here's my definition of platform. I spent a year developing it while writing my book and I've been building on it in continuing conversations with others since my book came out.
In blogs and websites that have interviewed me, clear credit is always given to me. These are my words. They are portrayed as my words.
Basically, your platform is everything you do with your expertise. A platform-strong writer is a writer with influence. Once you establish a platform, it can work for you 24/7, reaching readers even as you sleep. Of course, this kind of reach takes time. If many others already recognize your expertise on a given topic or for a specific audience or both, then you likely have an active platform.
I find it helpful to define a platform as a promise writers make to not only create something to sell (like a book), but also to promote it to the specific readers who will want to purchase it. This takes both time and effort, not to mention considerable focus.
Author of Get Known Before the Book Deal & Writer Mama
(both from Writer's Digest Books)
I do not believe that I have "cornered the market" on platform development or anything like that. I am absolutely not trying to do that.
I would just like to be given credit for my words when folks quote me. That's all.