When I look at that list I see that you have created all kinds of content that would be really good for the blog.
For example, I very frequently take comments I've made to discussion lists and post them to my
same thing with the papers and the course proposals and even some for the Twitter stuff. All of this would make great material for a blog post - even if you can't share it all, you can share some of it.
The whole point isn't to *add* online writing on top of everything else you do. Nobody has time for that.
Rather, what you want to be thinking of doing is to gradually migrate to writing online *instead* of writing for those other purposes.
That doesn't mean you become a blog writer and nothing else. Rather, what you'll find is that writing for the website makes writing for all those other things a lot easier.
The idea is to take the stuff you do for private audiences and to present it (as much as you can) to public audiences.
And you'll find you have people reading your work, helping you with resources and links to do the work you're doing now.
All this, at least, is my experience (and you'll find this comment on Half an Hour as well :) ).