I used to maintain a blog in Russian, in large part because I didn’t feel back then that I had anything to contribute to a more global community. This has changed! However, once it did, I no longer felt that blog is an appropriate format for this.
Blogs are inherently linear and chronological. But as the world evolves, so should the knowledge about it, and blogs aren’t a particularly great format to go back and update past posts in.
There is pretty much one thing they’re good for: news and updates. About whatever, as long as they are inherently attached to moments in time.