There is an old add-on from Firefox called Brief. It takes your Live Bookmarks (RSS feeds) and wraps a nice GUI around it so you can use your Live Bookmarks eff

There is an old add-on from Firefox called Brief. It takes your Live Bookmarks (RSS feeds) and wraps a nice GUI around it so you can use your Live Bookmarks effectively like how other RSS readers behave. Firefox syncs all of your bookmarks which would include your Live Bookmarks/RSS feeds. Assuming (I have not tested it yet) that this sync process retains the state of your read/un-read items, this could potentially be a hybrid solution where you are using a locally installed feed reader, while at the same time you can sync your data without loosing its attributes. Does this make any sense? I'm not a developer, just a reader.