Yes please!! This is the feature I always find myself wanting. (Using Akregator / Kontact in KDE.) So many stories are duplicated at various stories that the ability to hide all but one where the target URL is the same would save lots of time.
Hey Taki, I've wanted that feature too and we built that into our social news site called The Shared Web (www.thesharedweb.com). The content is pulled from Twitter or posted by other people on the site and aggregated by URL. We'll be looking into pulling directly from sources so you can follow RSS feeds too soon. Would love to know if it works for you.