The good news is that Google finally solved two big problems for Blogger authors: comment spam and managing comments. If Gmail has a great spam filter, why Blogger can't use a similar technology to detect spam comments?
"Blogger now filters comments that are likely spam comments to a Spam Inbox, much like the spam folder in your email. When someone leaves a comment on your blog, it will be reviewed against our spam detector, and comments that are identified as possible spam will be sent to your blog's Spam Inbox, found at Comments | Spam," explains Blogger's help center.
Blogger's spam filter works well and you can improve it by clicking on "Not spam" next to a false positive or mark as spam a message that hasn't been filtered.
Now it's easier to manage the comments from your blog even after they're published. The new Comments tab lists all the published comments and lets you delete them or mark them as spam. You no longer have to visit each blog post and manually remove spam comments.
Blogger's help center says that the Comments tab should be displayed even if you don't enable comment moderation. Unfortunately, the tab disappears when you disable comment moderation. As Blogger's blog admits, comment moderation can be annoying. "To fight spam, some of you enabled moderation of all comments or required word verification or login. While somewhat effective, these checks limit real-time conversations around your blog."
For now, I've enabled comment moderation for posts that are older than 30 days. Hopefully, you'll no longer see spam comments.