With Google.com virtually the only game in town, it's good to see new engines like Teoma* every now and then. So I was really pleased to stumble upon Roogle earlier this year. I played with it a little bit and submitted our site. But I didn't spend very much time with the engine. This past week, the company changed its name (for obvious reasons) from Roogle to Feedster and is hard at work serving up search results not from site spiders but from RSS feeds. With its new name and nearly 14818 posts and over 1309 RSS urls, I think I'll spend some more time there.
The importance of this should be immediately clear. When you publish to the Web, you create two types of documents, those that are meant to be searched, and those that are not (like pages that contain nothing but indexes of stories, for example). By focusing on RSS feeds, Feedster bypasses this problem elegantly, letting the searcher look only for documents that are deemed readable, useful, even desirable. Of course it can return results as RSS feeds.
*I highly recommend Teoma, BTW. This engine not only organizes results by popularity, it presents meaningful collections of relevant sites, allowing users to quickly refine and re-refine a given search query. Pretty spiffy.