One important part of your platform is building your email list. It might not be fun and I might not like lists, but they matter.
One way only you can build your list is to offer something only your can offer.
This free gift for signing up could be a short story in your setting or including your characters before the story starts.
If you write non-fiction you could write a short guide to your topic.
Whatever it is that you write, only you can offer it as a list joining gift. Libre Office and Open Office both have the ability to export a document as a PDF. You could create a PDF that is just for your most loyal fans (list subscribers).