Don't waste words
Whenever you have an idea, a strategy, even a glimmer of an idea, write it down. Don’t figure you’ll remember it. Don’t talk about it with someone before you’ve written it down. Have a place to put it -a notebook, a pocket computer, an index card you carry with you (...); develop the habit of always writing down those bright ideas that come to you while you’re on the run
Here I see an advantage of a blog, wherever you are, if you have access to the internet, then you don’t need to worry about having a notebook and a pen. As long as you are connected the WWW you will have access to your diary all the time.
Blogs help to keep track of additions to specific entries in your blog, they also help keep some entries private while you are working on them (you can make them public afterwards), or if you have a private entry you can still give access to your supervisor or a friend.
This may be a good motivator if you have a class and your students see your blog, it is a different and interesting way to know your lecturer. I have seen other lecturer-writer-researcher doing this. It must have its benefits if they keep doing it.