Weeks ago, I read a blog post that I found off of Hacker News which apparently was published many years ago.
It was something to the effect that everyone should blog even if you don't have any readers. It makes a great argument that writing
down your ideas makes them concrete (it adds a personal value) as well as making you a better reader as opposed to just keeping them in your head.
The concept is similar to telling or teaching someone what you just learned and recalling every bits of details to make the other person
understand. It forces your mind to think and makes a good challenge to yourself in finding out how much you really know about the subject.
I find that this is also true when it comes to presentations or writing a book (not that I've written one) but having to present those ideas
to an audience requires you to research and dig deeper to fill in the gaps.
The transfer of knowledge is valuable to the receiver (readers or listeners) as well the person telling the story.
I subscribe to tons of blogs and knowledgeable people in the web development industry, and read tons of articles on a daily basis. I also
buy digital books from sources such as LeanPub from time to time just to read up on new concepts and ideas. I love the fact that
websites like LeanPub allows any person to publish and share the ideas with the world in a much simpler process. There's no
publisher that gets in the way of the publishing process -- and the subscribers gets any updates instantaneously.
Anyone with a passion towards a subject should blog about it because it's good for you and everyone!
In terms of knowledge about the subject, it's been said that you don't really own what you know until you can repeat it and say it out loud.
Having to write about what you know will make you realize how much you know and don't know, plain and simple.