Blogging about a topic that interests you can be a useful method of self-education.
-The pressure to post at least a little bit every day or so is useful if you are trying to learn more about the topic of your blog; it's a fun way of imposing some discipline on your studies.
-If one of the purposes of your blog is to share links to articles and websites about your topic, the act of finding articles and websites to link to can serve as a useful reminder to read widely about your topic and keep up with the latest news and opinion about it.
-Becoming a blogger means getting into the habit of writing regularly and articulating your ideas in a compelling way; developing your verbal and writing skills is essential to your self-education regardless of what you study.
-The act of writing (and re-reading what you write) about a topic helps you better retain and recall what you have learned.