Rather than being a news reader, Rolio would best be described as a "river of updates" service in the likes of a Twitter or Facebook app. Instead of trawling your RSS feeds and serving up posts for you to read, Rolio merely offers a link much like what you would see on Twitter. It can also serve up the latest updates from your Twitter or Facebook accounts, and you can tweet from Rolio.
You can focus on a stream of updates from a single RSS feed by clicking on one of the icons at right (see the recently added panel), and you can also sort your feeds into groups. Unfortunately Rolio doesn't appear to respect the folder organization i created in Google Reader. It also won't let me import my full list of feeds.
It is of course possible to subscribe to feeds or import your own OPML file (up to a limit), but I'm not sure that Rolio is really intended for anyone who follows a lot of RSS feeds. I think Rolio would be of greater use to anyone who gets their news via one of these social networks. This service gives the more social reader a place to consolidate their Facebook and Twitter sources into a single clean stream.
Rolio is currently free and available only in the web browser. Apps for Android, Windows 8, iPad, iPhone, and WIndows Phone are in the works.
I for one never plan to use this service once I close the tab today. While I can see the utility, the fact that this is a stream of updates makes it completely useless to me. If I am using it as a news service then I need to know what I have missed while I was away. And frankly, Twitter isn't all that important to me as a news source, so I don't want the tweets getting in the way of links to news.
Also, I found while using Rolio that the tweets tended to completely overwhelm the blog post notices. There's a volume problem here, and if I had added enough RSS feeds to balance out the many tweets the updates would be going past so quickly that I don't know that I would be able to catch them all.