It could be the summer, vacations, etc. I haven't seen that, but I visit and comment on other blogs, so I tend to get some feedback.
Try some different tactics with the "titles" of your posts. Most time I didn't know what your topics were about unless I clicked on them when I checked out your blog. Also, try another plugin (not sure what they have for blogger) because everyone might not have the options available to leave a comment.
Here are some you can check out:
Intense Debate
Comment Luv
disqus
Give it time, things will pan out especially during the holidays.