Lurkers dominate every online community. The percentage of those who actually participate is probably under 10% ... and often, a LOT less. But here's the thing. We're dealing with social networking here. People come to a blog to learn, and one way that happens is through interaction. A blog that gets a constant stream of comments is way more appealing to readers than a blog that doesn't. 

How can you get more comments on your blog?

1. Ask what a reader thinks of this (post, idea, etc.). Just the suggestion will sometimes get the reader to cross that great barrier from non-participant to participant.
   

1. Ask any question, especially in the title of your post. It gets the reader thinking, especially if they have a totally different answer from what they already see, or if they disagree with what they see.
   

1. Ask, "Do you have any experience with ‘apples’? If so, what happened?" Someone with specific "apples" experience is now expressly invited to comment, and some will.
   

1. Always respond to comments. Train yourself to see the value in every comment, and then tell the value you see. If you don't, you'll lose people. They'll feel you think you're too good for them or that you don't value their input. The more you interact, the more comments you'll get ... and your readers will see your blog as a "happening" place. And, over time, some readers will get more active and answer other reader questions, freeing up your time.
   

1. You need to be a leader AND, to get the best response from your readers, you need to be human. If they think that you may think less of them or ... worse ... respond negatively to a comment, then there's no way they'll take the chance. But if you are obviously good at what you do AND you are humble and gracious and good-natured, then you make people feel safe in participating.
   

1. Keep it simple. If you ask people to register before making a comment, very few will bother. You will lose most of your comments. Let them comment with no hoops to jump through.
   

1. Where you can in your blog posts, link to a related comment. You reward the reader who made the comment, and you highlight your comment section and encourage others to participate.