Doing background study on something to write about can be fun. But, unlike when you have actual set goals to achieve there is the danger of getting carried away. There is always something more to learn, or just some interesting side tracks to explore. It's just so much more fun than actually writing about it.
That's a problem when you are doing something without clear responsibility to deliver. In this case, it's not that dangerous. I just won't get the post written and have to write about something else instead. But at the same time I keep learning something new. Perhaps nothing useful, but learning none the less.
Is my goal the learning itself, or the writing? I'm not accountable for anybody on this one, except for myself. And as long as I'm happy it doesn't really matter. It offers me something meaningful things to do. Maybe, at some point I'm confident enough to write about some of those topics. And in some cases, the information I learn might actually end up being useful too.
Or perhaps I could write about how much I know so far, and iterate the topic over while I'm learning more. I don't have to sound like an expert on the first try. It's supposed to be a learning journey after all.