I'm not exactly sure what I'm seeing here, but Voyage, by Andy Biggs, is an abstract RSS reader that places posts in a 3D cloud. As you click on items, you can drill down further to later posts. You can also use the up and down keys on the keyboard or the scroll wheel on your mouse. (The latter isn't working for me right now.) For example, press up and you'll see earlier posts from your subscribed feeds. The horizontal placement doesn't seem to have any significance.
It's probably best to take Voyager for what it is. After all it was just meant to be an experiment in 3D Flash. It's pretty to look at and fun to play with, but not so much about practicality.
[via can't remember]