How do you decide you have an idea worth writing about?
A common notion is that elaborate planning and research precedes writing. That we ought to start writing only when our idea is well formed. For most forms of writing (except scientific or technical writing) this is a misconception.
Daniel Pink talks about how he writes his books. He starts off with a hint and bangs away at the keyboard for several days. Only after he has written a 30 page proposal does he know if his idea deserves to be a book. He does not write when he has things figured out. Instead, he writes to figure them out.
Writers do not have a map when they start. Instead, they pick a direction and explore their mental jungles using their keyboards.
When I write my posts, I often end up at a different place from the one I had intended. The creation of every post is an exploration. And the post itself, the words scrawled on the screen when I am finished, is the map.