If someone comments on your blog post, you should always try to respond. If you don’t, it shows readers that you don’t care about the comments or possibly you don’t even read the comments. [sidenote: not ALL comments by readers deserve a response; but if you have a low comment rate on your blog, you should try to respond].
One of the worst things a blog owner could do is allow their posts to have just one comment. A reader spends the time to read your post, share his/her thoughts, and then crickets. Not quite the message you want to send to your readers.
Every blog should have a community where people interact with each other. If you can’t even respond to the comments on your own blog, I seriously doubt why anyone should read your blog.
Often when my own blog post has zero comments, I’ll be the first person leave a comment just to show people that yes, the comments section is active. That would be the only time that one comment is acceptable on a blog, is when it’s by the blog author. Although it kinda saddens me when I have a bunch of one-comment blog posts, and they are all by me. But hey, at least I’m trying to engage my audience.
Please, bloggers, respond to your reader’s comments.