It's a new open source project, so I have no idea if it has any legs (the last Big Project That Would Change Blogging Forever was [StructuredBlogging](http://www.darcynorman.net/2005/12/14/structured-blogging-semantic-web-for-the-rest-of-us/) and the StructuredBlogging project and site went dark long ago...)
From the [SocialRiver website](http://socialriver.org):
> SocialRiver is based on open source libraries and the OStatus specification, which includes direct support for Webfinger, ActivityStreams, Salmon, and PubSubHubBub (PuSH). We also support OpenID and will add support for OAuth and other technologies, including Websockets.
They're also offering a hosted service, if you don't want to install and run your own SocialRiver (which takes care of the n00b/Grandma problem). It's built on top of WordPress, so it may integrate with an existing blog. Not sure how that'd work or look. But interesting.
I'll have to grab a copy and play, to see how a distributed social network might work. There's already an installable package on the site, as a plugin that drops into an existing WordPress site...