I've had complaints (justified) that certain topics of importance get hijacked by readers wanting to talk or link to other subjects. That hasn't bothered me but on some topics I want the conversation clean. I want us to stay on topic.
My solution was to make what Blogger calls a "web page" (a stand alone page on the blog) but after a bit of reflection I realize that it wouldn't work.
The solution is simple. A little comment discipline is needed. When a topic is of importance then you'll see a "*" before and after the title. No off topic comments will be allowed. I'll simply delete them. I'm going back one day and instituting this system.