Indeed it does what RSS used to do for me. It also adds comments and pictures, something RSS could also do depending on the reader. The real added value of G+ compared to RSS is the original content: a lot of people in Open Source and science, for example, use it as a blog platform. I do wish social networks were less ghettoized, but as a publication medium it doesn't seem less open than a blog to me. There are even tools to generate RSS feeds from G+ streams I think.