Blog comment ettiquette, how to give feedback to the blogger

Here's a question about blog ettiquette, with regard to comments and the topic of a blog post:

In general, is it appropriate to make comments on a blog post that are not relevant to the topic of the post itself?

My own view is that it is not appropriate to post comments that are off-topic for that post.

But, sometimes, I have comments on style or the overall blog, or questions, etc. that are not related to a specific blog post. In those cases, my preference is to send an email to the blog author, rather than clutter up a blog post thread with off-topic comments.

Here's an idea I just came up with: periodically write a post that is specifically entitled "Blog Feeback", "What do you think about this blog?", "It's feedback time - What can we do to make this blog better?", "Any suggestions for this blog?", "Suggest a topic", etc., and then people have a place to do any off-topic feedback, comments, questions, general ranting, etc.

With that in mind, I'll follow this post with such a post.

Note: My motivation for this post was a post by Dave Taylor entitled "Let's Play 'You Be The Blogging Consultant'" in which he gives a list of blogs of his clients and suggests that we "visit one or more of them, evaluate what they're doing, and then post a comment here with your feedback to that blogger." That's a great idea, but it does mean that the feedback is separated from the blog itself and readers of the blog who haven't visited Dave Taylor's site won't know about the existing feedback or that his blog is where you are supposed to go to give feedback. And not knowing about the off-blog feedback area, readers will be more likely to either clutter up the blog with off-topic feedback, or, even worse, not give feedback at all. I like my approach better.

-- Jack Krupansky