Attensa has introduced a very comprehensive RSS metasearch tool:

RSS doesn't add much value for immediate searching. When the information we need is dynamic and unfolding over time, RSS searching is incredibly powerful. The newest version of our RSS reader, Attensa for Outlook, gives you the ability to perform unlimited RSS searches across 18 search engines by simply typing the keywords that are the center of your attention. Enter the keywords once and search across Blogdigger, Daypop, Digg, Feed24, Feedster, Google Blog Search and Google, IceRocket, MSN Search, Plazoo, SeekItAll, Technorati, Wikipedia, Wired News, Yahoo! and Yahoo! News (if we're missing any let us know). New information is sent to you every time information relevant to your search is published. The information you seek is delivered to a single Outlook folder labeled with your keyword or separated into folders organized by search source and keyword(s), whichever you choose. With this single expression, you turn an AttentionStream into a continuous river of attention.

Smart!