I must have missed this in the announcement. When you set your blog to either private or invisible to search engines, you get your tags back. You know, the tags that you assign to your posts. The tags above this post link to the global tag page, and the only way to view this blog by tag is to dig through my ‘history’ page, and the unwieldy list of tags there.
It makes sense, since private and unsearchable blog posts don’t show up on global tag pages, so there would be no way for users to click back to the private blog. pretty cool.