Google+ Is Walking Dead
Google+ could still win by exploiting a simple heuristic: Don't be Facebook. Allow for privacy, allow for handles, integrate seamlessly with platforms that have traction already (including Facebook). Remember how Instagram let you take a photo and publish it to multiple services (Twitter, Flickr etc)? It was a free, useful tool that made your life easier and made you look great. It had a feed and following on top, but it wasn't clear in the beginning it would even be a social network on its own.