Google has just announced that Blogger can now display comments submitted by your Google+ contacts. Blogger already provides the option to automatically post your new blog posts to Google+; as best as I can tell from the screenshots of the new service, comments made on your Google+ post can now appear on your blog.
I don't yet know if comments made directly on your blog by people who aren't on Google+ will appear on Google+. The new option hasn't yet been enabled in my Blogger dashboard so I can't check for myself; my older cross-posts with comments in Blogger do not show up on Google+ as having comments, but that doesn't mean that it won't work that way moving forwards.
This move is doubtless in response to the shared Facebook comment streams that are finding increasing use. Bloggers posting a link on their Facebook page to one of their blog posts can set up a similar two-way interaction. It solves the problem of where to comment - on a friend's blog directly, whose archive they control? Or on their Facebook page where the interaction might be seen by more people?
I haven't spent much time on Google+, but I know people who do. A truly integrated comment stream would be a welcome addition, and might actually get me to connect with more people in Google+. At present, my blog has trimmed back down to much like what it was in 2008: public but unadvertised, read by only a few family members and local friends. I still co-organize a blogger group, but my outreach died down with the decrease in activity of the Cleveland Social Media Club. That could change.