Some readers of this weblog may not be aware that I use Radio to read my RSS feeds. All the RSS machinery in Radio is available to be modified; without it you wouldn't have extensions like outlining and categorization, as provided by myRadio and soon activeRenderer.
As the number of RSS feeds I subscribe to doesn't seem to be decreasing, hierarchical and categorized views can help. I find a browser- and weblog-integrated aggregator much more useful than a desktop one such as NetNewsWire. Typically I read through a page of stories in Radio's aggregator under Chimera, Command-clicking on each link that looks interesting to open it in a background tab. Then I read through the open tabs, click “Delete” to get the next page of stories in the aggregator, and repeat. With NetNewsWire currently, I could open the links in the background, but when (unfortunately, not “if”) Chimera crashed I'd have to figure out which articles I had read and opened links from. Radio's batch-deletion approach handily sidesteps the issue. Finally, I like the mostly passive experience of reading through the news in a single Web page, rather than the active approach of having to press the space bar repeatedly to browse.
However, the integration advantages of a Web-based aggregator on the Mac can and should disappear when the Safari SDK is made available. Windows users have had similar opportunities for years through the embeddable IE control.