The default commenting settings on Blogger makes no sense to me. Commentators need to have a Google Account and you are not notified when someone comments on your blog.. I recommend changes the following settings:
Who can comment? "Anyone - includes Anonymous Users", changed from default: "Registered Users - includes OpenID" because anyone should be able to comment on a blog.
Comment Form Placement "Embedded below post", changed from default: "Full page" so no need to click for a new page.
Comment Notification Email Make sure you enter your e-mail address here. I can't remember the last time I received comment spam on my blog so the spam protection in Blogger is quite good - no need for moderation unless you have other reasons for it.