This is definitely not a surprise. Facebook Comments has become a very powerful platform and now Google has their own similar platform but currently restricted to Blogger platform.
Blogger users can now switch to Google+ powered commenting on their blogs. The benefits are that visitors can now share your post with friends using the comment box itself. They can generate their own stream of comments focused on the blog post.
Comments can be made private with your selected members. Blog owners get to access all the comments at a single location. It’s pretty cool. We hope Google makes it available through an API so that other blogging platforms can also make use of this platform.