You can.
Go to your Blog control panel and see the options there.
Default Subscription Mode: Blog Entries
When you post a new blog entry, you can choose to automatically add the entry to your list of subscribed entries, with the option to receive email notification of new comments to that blog entry.
Default Subscription Mode: Blog Comments
When you post a new comment, you can choose to automatically add the blog entry to your list of subscribed entries, with the option to receive email notification of new comments to that blog entry.
Default Subscription Mode:
You can also subscribe to other user's blogs, etc.