Benjamin Pasero has posted the first release candidate of RSSOwl 1.0, an open source RSS reader written in Java and based on the SWT toolkit. RSSOwl is the best open source RSS client I've seen written in Java. That said, it still doesn't feel right to me. Even ignoring various small bugs and user interface inconsistencies, news just doesn't flow in this client. The three-pane layout that separates the news item titles from each news item, and place the news item titles above the text of the news item doesn't work well for me.
The Mozilla Project has released Sage 1.3, an open source RSS plug-in for Firefox. Overall, I think this works better than RSSOwl. It also uses a three pane layout, but one of the panes is almost a full sized browser window, and includes complete news items, one after the other. This is almost good enough to actually use. However, it's got three major missing features:
Both RSSOwl and Sage still feel like toys to me, not serious tools. Neither of these products seems capable of handling hundreds of blogs and thousands of news items. Oh, don't get me wrong. I'm sure you could subscribe to hudnreds, probably thousands, of feeds in either one of them; and it wouldn't crash or slow down. But the user interface is just not adequate for managing such large, ongoing, constantly updated information collections. So far I'm not sure if there is an RSS client that is capable of this. I don't know what a good RSS client will look like, but I'll know it when I see it, and so far I haven't seen it. RSS feeds are a new way of interacting with information, and we need some serious user interaction studies to understand how to properly design new user interfaces that fit. The old metaphors aren't working any more.