...but you cannot make him post comments on your blog.
I've introduced blogging at work. It's been reasonably successful. I had a recent post where I proposed a new marketing strategy. The post got several hits because I sent the link out via email to people I thought would be interested. In the email, I ask for comments on the blog post. One email recipient forwarded on the email to another person and they proceeded to discuss it via email instead of posting comments.