I tend to go down rabbit holes thinking about things. Distilling experiences to try and understand it and extrapolate from them.
It is easy to miss something if I do not expose these ideas to the world. Talking is good. Writing is better. As a conversation goes on its foundation can get blurred through memory. With writing I can always revisit exactly where you started.
Manifesting an idea very quickly shows whether it is novel, interesting, logical, consistent, challenging. It also enables me to bring the idea to some form of completion. By writing an idea down it becomes concrete. It will not just disappear, or bend.
This does not, however, necessitate publishing what I write.
Adding my thoughts to the multitude of others on the internet lends a little more importance to actually writing down what I am thinking. Maybe someone else will find it useful. This helps motivate me to actually follow through on my ideas by making them concrete.
The other reason I publish what I write is for accountability. Just like the ideas themselves the identity they make up can easily and conveniently disappear, or bend depending on the situation. This ambiguous identity enables me to fit in, but can prevent me from being understood and can lead to me compromising what I believe in and care about.
Publishing the ideas that my identity consists of makes my beliefs more concrete and makes it possible for me to be held accountable to those beliefs. Regardless of whether that means changing my behavior, or my beliefs, it facilitates conscious belief and action.