Here are a couple initial thoughts about Google Plus:
1) I would really like to be able to create some content (like a photo album), and publish this to my circles, using different contexts for different circles. Fine grained, but I think this would be really cool. When you post on your blog, you post photos and then you write a story, and you think the story is the content. But when the post comes up as a result of a google search, it's the pictures - the real content - which you see. With short posts (Twitter, Posterous, Facebook, Google+), it becomes more obvious that what is readily shareable is videos and pictures (my content), not words (my context).
2) Because I can't access Twitter during the work day due to a firewall restriction, I appreciate how several techies I follow collect a week's worth of tweets into "Short Form Fragments" - why couldn't Google+ automatically do this for me, collecting a weeks "stream" into an automatic blogger post? Again, this would be very cool.