Google+ is gaining popularity quickly and looks like it is already one of the preferred social networking platform with more than 10 million users. Since you might be following many users on Google+, you might want to keep track of any particular users or a blog on Google+. You can keep updated with all the posts using the RSS feature. You can subscribe to RSS feeds for any user using this tool- Google+ User Feed. It converts any user profile into RSS feed.
All you need to do is to get the profile ID of any user, this can be found from the profile. The digits at the end of the profile is the ID for any user. For example, this blog has profile as https://plus.google.com/u/0/109296690523645668017. So the profile ID is 109296690523645668017.
To get the RSS feed, add the profile ID to this URL- http://plusfeed.appspot.com/, which means the RSS feed of this blog is http://plusfeed.appspot.com/109296690523645668017. You can add this URL to Google Reader and keep updated with all the posts from the user.